Adams Township is located in the southern edge of Butler County, Pennsylvania and was incorporated at 1854.
Early activity in Adams Township was largely clearing woods for agricultural use and the occasional saw mill and tannery. in 1878, the Pittsburgh and Western railroad, later the Baltimore and Ohio, built its track along the Breckneck Creek Valley and development began along the corridor. The communities of Mars, Callery and Valencia sprang up quickly between 1875 and 1900, and by 1905 all three were separate boroughs, extracting over 600 acres, now 828 acres, from the Township. For a time, most of the residents, in what was originally Adams Township, loved in the three boroughs. Bu 1920 two-thirds of all residents within the outer boundaries of Adams Township live the Township.
There was not a good east-west connection across Adams Township. Even as suburban development pushed north from Pittsburgh along Routes 8 and 19 on either side of Adams, a trip between these two highways involved use of the two-lane country roads a disjointed route that passed through Mars. In the 1950's, the present Route 228 alignment was built, providing a continuous connection between the two-major north-south four lane highways, avoiding congested Borough streets in Mars.
It is clear that the population of Adams Township is changing. Once a stable, predominately agricultural community, over the last couple of decades, it has been slowly transforming into more of a suburban bedroom community where the majority of residents commute to work outside of the Township (and the County). The influx of new residents into Adams shows that approximately 44% of the people who live in the Township have moved into their houses since 1980. As new residents move into the Township, Adams is becoming more diverse in terms of outlook, education, occupation and household size.