What was the most significant event on April 28 during the U.S. Civil War?

Pictures:
1 1862 New Orleans Map;
2. 1862 Union Fleet New Orleans;
3. 1864 Fortress Monroe, VA;
4. 1865 Cleveland Lincoln funeral train public square
In April 1861 every US Army soldier who was stationed in what was becoming the Confederate States of America was in peril of capture or being killed. After the surrender of Fort Sumter, most commanders instructed their forces to leave the areas in an orderly manner without engaging in hostile actions.
The 8th US Infantry Regiment had been stationed in Texas since 1845 when they were sent to Texas to fight in the Mexican American War. The 8th US Infantry Regiment was captured piecemeal in Texas after being ordered to leave Texas by way of the coast. Companies A and D were captured at Indianola, April 24, Company C was captured at San Antonio on April 28, and Companies B, E, F, H, I and K, under Captain I. V. D. Reeve, near San Lucas Springs, about 22 Miles west of San Antonio, May 9th. Company G had been broken up.
The POW enlisted men were held until February 25, 1863, during which time they were divided into squads and removed to different posts on the frontiers of Texas, deprived of pay for more than two years, supplied with scanty food and clothing, and made to suffer severe military punishments. CSA recruiting officers visited them daily, offering them commissions and large bounties to desert their flag,
1865: Lincoln's funeral train in Cleveland. Abraham Lincoln's funeral train stopped in Cleveland, Ohio. Because Cleveland lacked a public building capable of accommodating a large crowd, Lincoln's casket was taken to a public square and placed under a gazebo. Cleveland's viewing was the only one to take place out of doors and an estimated total of 150,000 mourners filed past the casket in about 15 hours.

Since RallyPoint truncates survey selection text I am posting events that were not included and then the full text of each survey choice below:
A. Sunday, April 28, 1861: Capture of Company C, 8th US Infantry at San Antonio, Texas. The entire regiment was captured piecemeal between April 24 and May 9. Some officers were paroled, some eventually switched sides and the enlisted men suffered under poor conditions and cruel treatment.
B. Monday, April 28, 1862: Surrender of New Orleans. After the blockade was established the Union Navy ascended to New Orleans to capture the city, closing off the mouth of the Mississippi to Confederate shipping both from the Gulf and from Mississippi River ports still used by Confederate vessels.
C. Tuesday, April 28, 1863 Grierson’s raid: Chance encounter leads to Union success when COL Grierson restored order fairly quickly and his men drove off the Confederates. Col. Benjamin H. Grierson's had halted his raiding party for a brief rest 2 miles east of Union Church, Mississippi. After a short time, they were startled by the sound of rifle fire as their pickets were being fired upon by a considerable sized force of Confederate cavalry. A battalion of Col. W.W. Adams' Mississippi Cavalry had stumbled upon Grierson's raiders. Adams' cavalry had thrown the Federals into a momentary panic. COL Grierson restored order fairly quickly and his men drove off the Confederates.
D. Thursday, April 28, 1864: Military attention refocuses on Fort Monroe when the Union Army of the James, with Benjamin F. Butler as commander, is formed. It will use Fort Monroe as a launching pad for moving against its twin objectives of Richmond and Petersburg in the war's final year.
Butler returned to Fort Monroe in 1864, when the new Union general-in-chief, Lieutenant General Ulysses S. Grant, devised his series of spring offensive operations against the Confederacy. Butler commanded the newly formed Army of the James, headquartered at Fort Monroe. The two corps under his command, including some twenty-five regiments of United States Colored Troops, were assigned to push against Richmond and Petersburg. Although Butler displayed no tactical brilliance in the ensuing engagements, his presence south of Richmond forced Lee to dispatch troops from the Army of Northern Virginia to meet the threat.
1. Tuesday, April 28, 1863 --- Central Virginia – Chancellorsville Campaign: Having camped near Hartford Church during the night, Hooker’s troops (V Corps, XI Corps, and XII Corps) continue their march in relative silence: The Confederates apparently have no idea that Hooker is stealing the march. Howard’s XI Corps arrives near Kelly’s Ford by 4:30 PM. A string of Federal pontoon boats arrives via the Rappahannock river, and are ready to cross the river by that evening. The Federal infantry begins their crossing.
Although Stoneman's cavalry has not taken up his disruptive post in Lee's rear, as per the original plan, Hooker has every confidence in the success of his planned move: so far, the Rebels are clueless.
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2. Tuesday, April 28, 1863 --- In the Vicksburg theater, Gen. Grant suggests that Sherman’s troops make a demonstration (i.e., an assault that is not expected to succeed) against Haynes Bluffs (near the place of his earlier defeat at Chickasaw Bluffs) in order to create a feint for Grant’s movement across the river south of Vicksburg. Grant knows that such a feint will be interpreted by the American public as a military defeat, yet Sherman answers in this vein: I will take, ten steamers and ten regiments, and go up the Yazoo as close to Haynes’ as possible without putting the transport under the rifled guns of the enemy. We will make as strong a demonstration as possible. The troops will all understand the purpose, and will not be hurt by the repulse.
The people of the country must find out the truth as they best can; it is none of their business. You are engaged in a hazardous enterprise, and, for good reasons, wish to divert attention; that is sufficient to me, and it shall be done. I will be all ready at daylight, and shall embark the men the moment Captain Breese notifies me he is ready.
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3. Tuesday, April 28, 1863 --- As he travels through Seguin and Gonzalez, Texas, Lt. Col. Arthur Fremantle of Her Majesty’s Coldstream Guards makes observations in his journal about the traveling habits of Southerners: . . . In the afternoon tobacco-chewing became universal, and the spitting was sometimes a little wild.
It was the custom for the outsiders [passengers who sat on the outside of the stagecoach] to sit round the top of the carriage, with their legs dangling over (like mutes on a hearse returning from a funeral). This practice rendered it dangerous to put one’s head out of the window, for fear of a back kick from the heels, or of a shower of tobacco-juice from the mouths, of the Southern chivalry on the roof. In spite of their peculiar habits of hanging, shooting, &c, which seemed to be natural to people living in a wild and thinly-populated country, there was much to like in my fellow-travellers. They all had a sort of bonhommie honesty and straightforwardness, a natural courtesy and extreme good-nature, which was very agreeable. Although they were all very anxious to talk to a European—who, in these blockaded times, is a rara avis—yet their inquisitiveness was never offensive or disagreeable.
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4. Tuesday, April 28, 1863 --- April 27-28 in Town Creek, Alabama - On April 27, Maj. Gen. Nathan B. Forrest joined Brig. Gen. Philip D. Roddey's Confederate cavalrymen as they were engaged with Union forces. They soon fell back to Town Creek, still fighting. On April 28, an artillery duel began along the creek during the morning. It ended when Brig. Gen. Grenville M. Dodge's Union troops crossed the railroad bridge, thus forcing Forrest's men to retreat eastward towards the town of Jonesborough.
{[mycivilwar.com/battles/1863s.html#sthash.olE0BHJO.dpuf
5. Thursday, April 28, 1864 --- Slowed by the Ouachita River, the Confederates under Gen. Sterling Price, in pursuit of Steele’s Federal troops, stop and build a bridge to cross the river. The day’s delay for the Confederates allows Steele to make a good head start on his pursuers.
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6. Thursday, April 28, 1864 --- Judith White McGuire, in Richmond, writes a heartfelt and anxious, brief entry in her journal: The country seems to continue quiet, but the campaign on the Rapidan is expected to open every day. Oh, how I dread it! The morning is bright and beautiful; it seems hardly possible that such strife is abroad in the land.
{[civilwarsesquicentdaily-wolfshield.blogspot.com/search?q=April+28%2C+1864
7. Friday, April 28, 1865: Lincoln's funeral train in Cleveland. Abraham Lincoln's funeral train stopped in Cleveland, Ohio. Because Cleveland lacked a public building capable of accommodating a large crowd, Lincoln's casket was taken to a public square and placed under a gazebo. Cleveland's viewing was the only one to take place out of doors and an estimated total of 150,000 mourners filed past the casket in about 15 hours.
{[civilwar-online.com/2015/04/april-28-1865-lincolns-funeral-train-in.html
A Sunday, April 28, 1861: Capture of Company C, 8th US Infantry at San Antonio, Texas
The only movements of the different companies in the early part of the year 1861 (except a change of station of Company K), were made in compliance with an order issued by General Twiggs, the Department commander, for the troops to leave the State by way of the coast. The attempt to comply with this order resulted in the capture of all the regiment by the newly organized military forces of the Confederate States.
Company C, on entering the plaza at San Antonio April 22, was surrounded by an overwhelming force and obliged to surrender. Lieutenant-Colonel Hoffman, commanding the regiment, and the regimental staff and band, were taken prisoners about 10 o'clock the same day at San Antonio. The regimental colors were not captured, and the manner in which they were saved is narrated by Corporal John C. Hesse, Company A, as follows: "A few days subsequent to the surrender, upon going to the former office of the regimental headquarters, the building being then in possession and under the control of the rebels, I met there Lieutenant Hartz, the regimental adjutant, and Sergeant-Major Joseph K. Wilson, 8th Infantry. Our regimental colors being in the office, Lieutenant Hartz proposed to us to take the colors from the staffs, conceal them beneath our clothing and try to carry them off. We did so. I took the torn color which the regiment had carried through the Mexican War, put it around my body under my shirt and blouse, and passed out of the building, which was strongly guarded by rebels. Fortunately the rebels did not suspect what a precious load we concealed with us, for if they had our lives would not have been worth much. We put the colors in one of Lieutenant Hartz's trunks, and next day left San Antonio for the North. On the route we guarded the colors with our lives, always fearing that the rebels might find out what we had taken away and come after us; but they did not, and we arrived safe with our colors on the 26th of May, 1861, in Washington City, and turned them over to the regiment."
For this act Sergeant Wilson and Corporal Hesse each received a medal of honor.
Companies A and D were captured at Indianola, April 24, and Companies B, E, F, H, I and K, under Captain I. V. D. Reeve, near San Lucas Springs, about 22 Miles west of San Antonio, May 9th. Company G had been broken up.
The officers of Captain Reeve's battalion were not paroled as the others had been, but were, with one or two exceptions, held prisoners at San Antonio for about nine months, when they were exchanged. The enlisted men were held until February 25, 1863, during which time they were divided into squads and removed to different posts on the frontiers of Texas, deprived of pay for more than two years, supplied with scanty food and clothing, and made to suffer severe military punishments. Recruiting officers visited them daily, offering them commissions and large bounties to desert their flag, With few exceptions, however, they repelled the bribes and avoided the treason. Those who chose a different course did it to escape their prison.
The officers of the regiment who took commissions in the Confederate service were: Major Theophilus Holmes, Captains Larkin Smith, E. B. Holloway, Joseph Selden and E. D. Blake; First Lieutenants T. K. Jackson, T. M. Jones, R. G. Cole and Lafayette Peck, and Second Lieutenants J. R. Cooke and J. G. Taylor. The opening of the Civil War thus found the Eighth Infantry with its officers and men either prisoners of war, or debarred by their paroles from serving against the enemy; and it was not until October, 1863, that a body which can be considered fairly representative of the regiment could be assembled.
The reorganization of the regiment began May 1, 1861, at Fort. Wood, N. Y. Harbor, where Company G was recruited. Company F was reorganized at Newport Barracks, Ky., in July, 1861. Company A at Fort Hamilton February 17, 1862, and D at the same station May 7th. B at Fort Columbus July 29; C at Fort Columbus April 15, 1863; E and I at Fort Columbus, May 22; K on the 9th, and H on the 12th of March, 1865.
{[history.army.mil/books/r&h/R&H-8IN.htm
B Monday, April 28, 1862: City of New Orleans, Louisiana surrenders
The Union's strategy was devised by Winfield Scott, whose "Anaconda Plan" called for the division of the Confederacy by seizing control of the Mississippi River. One of the first steps in such operations was the imposition of the Union blockade. After the blockade was established, a Confederate naval counterattack attempted to drive off the Union navy, resulting in the Battle of the Head of Passes. The Union countermove was to enter the mouth of the Mississippi River, ascend to New Orleans and capture the city, closing off the mouth of the Mississippi to Confederate shipping both from the Gulf and from Mississippi River ports still used by Confederate vessels. In mid-January 1862, Flag Officer David G. Farragut had undertaken this enterprise with his West Gulf Blockading Squadron. The way was soon open except the water passage past the two masonry forts held by Confederate artillery, Fort Jackson and Fort St. Philip, which were above the Head of Passes approximately 70 miles (110 km) downriver below New Orleans.
From April 18 to April 28, Farragut bombarded and then fought his way past these forts in the Battle of Forts Jackson and St. Philip, managing to get thirteen of his fleet's ships upriver on April 24. Historian John D. Winters in The Civil War in Louisiana (1963) noted that with few exceptions the Confederate fleet at New Orleans had "made a sorry showing. Self-destruction, lack of co-operation, cowardice of untrained officers, and the murderous fire of the Federal gunboats reduced the fleet to a demoralized shambles."
Major General Mansfield Lovell, Commander of Department 1, Louisiana, was left with one tenable option after the Union Navy broke through the Confederate ring of fortifications and defense vessels guarding the lower Mississippi: evacuation. The inner ring of fortifications at Chalmette was only intended to resist ground troops; few of the gun batteries were aimed toward the river. Most of the artillery, ammunition, troops, and vessels in the area were committed to the Jackson/St. Phillips position. Once this defense was breached, there remained to face Union troops and warships only three thousand militiamen with sundry military supplies and armed with shotguns. The city itself was a poor position to defend against a hostile fleet. With high water outside the levees, Union ships were elevated above the city and able to fire down into the streets and buildings below. Besides the ever present danger of weather-caused breaks in the levees, now an even greater threat to New Orleans was the ability of the Union military to cause a break in a major levee that would lead to flooding most of the city, possibly destroying it within a day.
Lovell loaded his troops and supplies aboard the New Orleans, Jackson and Great Northern railroad and sent them to Camp Moore, 78 miles (126 km) north. All artillery and munitions were sent to Vicksburg. Lovell then sent a last message to the War Department in Richmond, “The enemy has passed the forts. It is too late to send any guns here; they had better go to Vicksburg.” Military stores, ships, and warehouses were then burned. Anything considered useful to the Union, including thousands of bales of cotton, were thrown into the river.
Despite the complete vulnerability of the city, the citizens along with military and civil authorities remained defiant. At 2:00 p.m. on April 25, Admiral Farragut sent Captain Bailey, First Division Commander from the USS Cayuga, to accept the surrender of the city. Armed mobs within the city defied the Union officers and marines sent to city hall. General Lovell and Mayor Monroe refused to surrender the city. William B. Mumford pulled down a Union flag raised over the former U.S. mint by marines of the USS Pensacola and the mob destroyed it. Farragut did not destroy the city in response, but moved upriver to subdue fortifications north of the city. On April 29, Farragut and 250 marines from the USS Hartford removed the Louisiana State flag from the City Hall. By May 2, US Secretary of State William H. Seward declared New Orleans "recovered" and "mails are allowed to pass".
{[en.wikipedia.org/wiki/Capture_of_New_Orleans
C Tuesday, April 28, 1863 --- in Union Church, Mississippi - On April 28, Col. Benjamin H. Grierson's had halted his raiding party for a brief rest 2 miles east of Union Church. After a short time, they were startled by the sound of rifle fire as their pickets were being fired upon by a considerable sized force of Confederate cavalry. A battalion of Col. W.W. Adams' Mississippi Cavalry had stumbled upon Grierson's raiders. Adams' cavalry had thrown the Federals into a momentary panic. Grierson restored order fairly quickly and his men drove off the Confederates.
{[mycivilwar.com/battles/1863s.html#sthash.olE0BHJO.dpuf]}
D Thursday, April 28, 1864: Military attention refocuses on Fort Monroe when the Union Army of the James, with Benjamin F. Butler as commander, is formed. It will use Fort Monroe as a launching pad for moving against its twin objectives of Richmond and Petersburg in the war's final year.
Butler returned to Fort Monroe in 1864, when the new Union general-in-chief, Lieutenant General Ulysses S. Grant, devised his series of spring offensive operations against the Confederacy. Butler commanded the newly formed Army of the James, headquartered at Fort Monroe. The two corps under his command, including some twenty-five regiments of United States Colored Troops, were assigned to push against Richmond and Petersburg. Although Butler displayed no tactical brilliance in the ensuing engagements, his presence south of Richmond forced Lee to dispatch troops from the Army of Northern Virginia to meet the threat.
{[encyclopediavirginia.org/fort_monroe_during_the_civil_war]}
Biggest Stone Fort in the U.S. - Fort Monroe - Virginia
https://www.youtube.com/watch?v=FR-AXRDHUds
FYI CSM Charles Hayden MAJ Dale E. Wilson, Ph.D. SSG Franklin Briant MAJ Roland McDonald SFC William Farrell SSG Franklin Briant SSG William Jones SSG Michael NollCPO William Glen (W.G.) Powell SFC Joe S. Davis Jr., MSM, DSL CMDCM John F. "Doc" Bradshaw MSG Andrew White SFC Randy Purham PO3 Phyllis Maynard Lt Col Charlie Brown Lt Col John (Jack) Christensen

Great read - thanks for the post.

Thank You COL., So Very Much for sharing this Military History. I Love History, more especially Military! You mentioned the landing below and Before Battle of Vicksburg. The Union Army made land fall on the Mississippi River around Port Gibson, MS. They were met by the CSA and actually outnumbered the Union but didn’t know it. After confrontation, the CSA pulled back and the Union went on up the River to The Vicksburg Battle. There is a hugh Military Cemetery in Vicksburg (I have kinfolks buried there). I was born in Yazoo City Mississippi. I worked at the Grand Gulf Nuclear Power Station, Phase 2, as a Electrician for a year at Port Gibson. There is a Civil War Museum and Memorial close to this Power Plant. Your comments brought back good memories from there and Vicksburg Cemetery. I’ve walked it many times. Thank You again Sir, for sharing this History. May God Bless You Always!!!