A Revenue Cutter Service name retained.
Morrill, a second‑class patrol vessel, was built in 1889 by Pusey and Jones Corp. for the Revenue Cutter Service.
During the period 1895‑98 Morrill, in company with cutters Boutwell, Colfax, Forward, McLane, and Winona, maintained a neutrality patrol off the Straits of Florida and adjacent waters. "The enforcement of neutrality laws," said Revenue Cutter Service Commandant Capt. Charles F. Shoemaker, "made necessary by many attempts to send illegal expeditions from our coast to Cuba in the interests of the insurgents, has compelled vigilant cruising by the Cutter Service." The cutters seized seven ships for violating neutrality regulations, detained a dozen suspected violators in port, and broke up two organized filibustering expeditions before the destruction of Maine 15 February 1898.
Morrill was transferred to the Navy Department by Executive Order dated 9 April 1898. Armed for service with the "Mosquito Fleet," she passed through Hampton Roads 24 April in company with cutters Hudson and Hamilton en route to Key West. She worked effectively with naval units during this duty with the fleet blockading Cuba. At the end of hostilities she returned to the Treasury Department and resumed patrol duty an the Great Lakes. Based at Detroit, she patrolled the waters of Lakes Huron, St. Clair, Erie, and Ontario, aiding vessels in distress and enforcing navigation laws.
One again made part of the naval forces, Morrill patrolled the Atlantic coast from 6 April 1917 until 28 August 1917. Several times she assisted merchant vessels that had grounded in her patrol area.
In early November Morrill was ordered to duty in Philadelphia with the 4th Naval District. She departed Detroit 10 November, Lt. George E. Wilcox in command. After a call at Quebec, she arrived Halifax the afternoon of 5 December. Dockside berthing was not available, and Morrill was directed to anchor near Dartmouth Cove totake on fuel and water.
Just after 0800, 6 December, the old French Line freighter Mont Blanc, carrying a full cargo of bulk explosives, was involved in a collision with the Norwegian steamship Iona in the Narrows of Halifax Harbor. A fire broke out on Mont Blanc, and at 0905 ship and cargo exploded in a tremendous blast that shook all of Halifax.
The most reliable casualty figures list 1,635 persons killed and 9,000 injured in the tragedy. Sixteen hundred buildings were totally destroyed, and nearly 12,000 more within an area of 16 miles severely damaged. Property damage was estimated at $35 million.
Morrill, not seriously damaged, turned her attention to the needs ashore. A rescue and assistance party under 2d Lt. H. G. Hemingway rendered valuable aid while the cutter stood by to tow other craft from the danger zone.
Morrill departed Halifax 18 December. Her services had come to the attention of Sir Cecil Spring Rice, the British Ambassador to the United States, in a letter dated 9 January 1918, Josephus Daniels, Secretary of the Navy, noted that Morrill, "though considerably damaged by the violent explosion of munitions on another ship, was the first to render assistance to the distressed inhabitants of the stricken city."
Upon arrival for duty in the 4th Naval District, Morrill operated as a coastal patrol craft for the duration of the war. She was reassigned to the Lakes Division 28 August 1919 and was most active in regatta patrols for the remainder of her commissioned service. After 9 years of service out of Detroit she steamed to Boston, where she decommissioned 19 October 1928.