Named for the "church on the hill," Churchill Borough has existed as a municipality only since 1934. However, the written history of what is now Churchill dates back to before the Revolutionary War, to a time when early settlers carved out farmlands from woodlands, and the French and British fought to establish ownership of the lands inhabited by Indigenous American tribes.

As the French and Indian War raged in 1758, British General John Forbes led an army of about 6,000 men over the Allegheny Mountains from Raystown (Fort Bedford) as they prepared for an assault on Fort Duquesne. Relying on the labor of their troops and recruited Pennsylvania settlers, Forbes and his second-in-command, Colonel Henry Bouquet, took six months to make the path passable for the army, artillery, and supplies. As the autumn leaves began to fall, the troops arrived at approximately the area that we know today as Bullock-Pens Park, where Forbes corralled a herd of oxen to be used as food for the troops.

Realizing they were no match for the British troops, the French set fire to Fort Duquesne, situated at the confluence of the Allegheny and Monongahela rivers, where they form the Ohio River. By the time Forbes and his assault forces marched into the smoldering ruins of the fort in November 1758, the French had fled down the Ohio River. After the fall of Fort Duquesne, a substantial number of Forbes’ men remained in a small village near the bullock pens to protect settlers against raids by the American Indians in the area.

By 1790, the area had become a safe home for the settlers. As more families established their homesteads and farms, there was a need for more efficient government than could be provided by Pitt Township, one of Allegheny County’s seven original townships. Wilkins Township seceded from Pitt Township on November 10, 1821, taking with it the area that is now Churchill Borough. Wilkins Township grew from a farming area to include manufacturing, and coal and limestone mining. The high ridge east of Wilkinsburg, near the intersection of what is now Greensburg Pike and Graham Boulevard, was named Lime Hill because of the kilns that burned constantly. Because of differing interests and needs among residents in various sections of Wilkins Township, a number of new municipalities were formed. The secessions began in the mid-1800s and continued into the 1900s. The land divisions created all the communities that are now part of the Woodland Hills School District, and also neighboring Penn Hills and Wilkinsburg.

Churchill Borough was the last new municipality to leave Wilkins Township. In 1934, a group of residents, Joseph M. Hollander, F.F. Roher, Harry C. Barton, Howard McCrady, and H.F. MacLane, dreamed of an ideal, small, quiet, and economical community where they could establish their homes and raise their children in an aura of peace and tranquility. But those were not the only reasons that 31 property owners sought independence from Wilkins. They were also driven by a desire for a lower tax rate after a reassessment by Allegheny County dramatically drove up their township property tax bills.

Many Wilkins Township residents objected to the efforts. They claimed that bonded indebtedness and outstanding bills threatened to leave Wilkins bankrupt should the secession effort succeed. Wilkins residents took their fight first to the Quarter Sessions Court and then to the state Supreme Court. While the high court granted the secession request, it would not let the new municipality establish its own school district as desired but required it to remain part of the Wilkins Township School District. In a formal secession from Wilkins Township, the Borough of Churchill was established on January 1, 1934. J.M. Hollander became the first burgess and Attorney Robert Fahringer was installed as the first magistrate.

Commercial establishments remain a very small part of Churchill’s land use. In 1956, the multi-million-dollar Westinghouse Research Laboratories (later known as Westinghouse Research and Development Center, and then the Science and Technology Center) opened on 354 acres of land originally purchased by Robert McCrea in 1773. Possession of the land passed on in 1807 to his brother William McCrea, who built a spacious farmhouse called Dundee Farm. Westinghouse eventually expanded the facility from the original L-shaped, red brick building and by the 1980s, the campus included laboratories, offices, programming facilities and more. Westinghouse acquired CBS in 1995 and changed its name to CBS Corporation. By the late 1990s, CBS had divested the last of the Westinghouse industrial businesses and Westinghouse’s remaining operations had moved to Monroeville and then to Cranberry. An effort to create the George Westinghouse Research and Technology Park had little success. Today, only one Westinghouse function is still located on the campus, which is now owned by Viacom. The buildings are mostly vacant, except for a portion used occasionally for movie and television productions.

The population was 3,157 at the 2020 census.