Saturday, July 24, 1915 was the day of the annual company picnic for the employees of the Western Electric Company. Seven thousand tickets were distributed to company workers and their families living in the Chicago area. The tickets were seventy-five cents each and children were to be admitted at no cost. The day's cruise was to take passengers to Michigan City, Indiana.

That morning, the Eastland was moored from its starboard side to docks on the south side of the Chicago River in downtown Chicago near the Clark Street bridge. The Theodore Roosevelt, the Petoskey, the Maywood, the Racine, and the Rochester were other ships chartered for the picnic and moored near the Eastland. Specific ship assignments had not been made for the employees. So, because the Eastland and the Theodore Roosevelt were the newest and most elegant, most Western Electric employees wanted to board these ships. And since these two ships were scheduled as the first to depart, there was little doubt that both would be filled to their capacities.

At 6:30 a.m., preparations began for loading. The river was fairly calm. There was no wind and the skies were partly cloudy. The Eastland was scheduled to depart at 7:30 a.m. At this time, 5000 people had already arrived and were waiting to board, so when the gangplanks were lowered, people rushed in so that they would not be denied a chance to ride the Eastland. The majority of those preparing to board the ships were actual employees of Western Electric. Because the company picnic was an important social event, a great many of the employees in attendance were young, single adults in their late teens or early 20s.

At 6:40, passengers began boarding the ship. At 6:41 a.m., the ship began to list to starboard (towards the dock), but this was not unusual as it was due to a concentration of boarding passengers who had not yet dispersed throughout the ship and were lingering on the starboard side. But, as the list hindered the continuation of loading slightly, the Eastland's Chief Engineer, Joseph Erickson, ordered the port ballast tanks to be filled enough to help steady the ship. By 6:51, the ship evened out.

At 6:53, the ship began to list again, this time to port. When the list reached 10 degrees, Erickson ordered the starboard ballast tanks to be partially filled. The list was straightened temporarily, but, as passengers were loading at an approximate rate of 50 per minute, the passenger count had reached capacity by 7:10. At this time, the ship began to again list to port. The port ballast tanks were emptied, but the port list increased to approximately 15 degrees by 7:16. Within the next few minutes, the ship straightened again, but the port list resumed at 7:20, at which time water began coming into the ship through openings on the lower port side. Even so, no great panic occurred among the passengers. In fact, some began to make fun of the manner in which the ship was swaying and leaning.

While this was occurring, the gangplank was closed and most passengers on the ship migrated to the port side where they had a view of the happenings on the river rather than a view of the dock. By 7:23, the list had become so severe that the crew directed passengers, many of whom were on the ship's upper decks, to move to the starboard side. However, by 7:27, the list had reached an angle of 25 to 30 degrees. More water began to flow into the ship from openings in the port side, and chairs, picnic baskets, bottles, and all sorts of items began to slide across the decks.

At 7:28, the list had reached 45 degrees. At this point, many of the crew began to realize the seriousness of the situation. Many more passengers were now on the port side of the ship, as they had gone there to view a passing Chicago fire boat that had sounded its whistle while passing. As the furnishings and appliances on the boat fell over with loud crashes and slid across the decks, the passengers began to panic. Many passengers began to crawl out of gang ways or other openings on the starboard side as the Eastland gently continued to list to port until it finally settled on its port side at 7:30.

Some passengers who had pulled themselves to safety were fortunate to find themselves standing on the starboard hull of the Eastland. Others who were not so lucky were trying to stay afloat in the currents of the river. Others were trapped within or under the Eastland. One eyewitness described the scene:

"I shall never be able to forget what I saw. People were struggling in the water, clustered so thickly that they literally covered the surface of the river. A few were swimming; the rest were floundering about, some clinging to a life raft that had floated free, others clutching at anything that they could reach--at bits of wood, at each other, grabbing each other, pulling each other down, and screaming! The screaming was the most horrible of all."

Other boats in the area and people nearby began helping with rescue operations immediately. Some onlookers dove into the river or jumped onto the boat to help those who were struggling while others threw wooden planks and crates into the water to help people stay afloat. The crews of other ships were pulling people out of the water, dead and alive. By 8 a.m., all survivors had supposedly been pulled out of the river. Ashes from the fireboxes of nearby tugboats were spread over the starboard hull of the Eastland so rescue workers would not slip on the wet and slick surface as they cut holes in the side of the hull to pull out survivors as well as dead. The screams coming from those inside the ship were disturbing for onlookers. By the time the holes were cut in the hull, many who had been alive at the time the ship rolled had since drowned. A great effort was expended to remove the dead from inside the ship as divers had to go underwater within the hull to retrieve bodies.

A major problem occurring immediately after the disaster was the vast amount of bodies that needed to be laid out in order to be identified. As the Western Electric employees were not assigned to ships, no passenger lists existed and none were written as the ship was boarded. By Saturday afternoon, the Second Regiment Armory on Washington Boulevard had been established as the central morgue. The bodies were set together in rows and around midnight on the 24th, those who believed their relatives might have perished were admitted to begin identifying. Identification took a few days since some entire families were wiped out in the disaster and no one was left in the immediate area to assist in identification.

The total death toll was 844 people. Eight hundred and forty one were passengers, two were from the crew, and one was a crew member of the Petoskey who died in the rescue effort. Although the Titanic, which sank three years before in 1912, had a higher total death toll of 1,523, the Titanic actually had a lower death toll of passengers than the Eastland as crew deaths from the Titanic totaled 694.

Salvaging the ship itself was not an easy task. While raising the ship, difficulties were encountered in getting it to float as so much water needed to be pumped out of the hulk. The ship was finally refloated on August 14.

The Eastland was acquired by the Illinois Naval Reserve four years later, after several modifications which enabled the ship to serve safely as a training vessel. The ship, re-named the U. S. S. Wilmette, served for several years until it was decommissioned in 1945. The ship was then sold for scrap, and by early 1947, the ship was completely disassembled for parts and metal.