The Town of Ayer grew up around the railroad industry in the 1840's and the railroad continued as a major force in shaping Ayer's economy through the early 1900's. Railroad switching yards, tanneries and mills prospered as a result of railroad transportation in the area which is now the Central Business District. Ayer is served by commuter rail service today and the town is within easy access of three major roadways, I-495, I-290 and Route 2.

While Ayer is primarily residential, the close proximity to these major transportation links fueled industrial development throughout the town which made the manufacturing industry the largest employers in the town in the 1980's. However, by 1990, the service sector had become the community's largest employer, followed closely by retail trade employment. Commercial activity and retail activity has continued to expand in Ayer.

The town is one of the four communities that serves as a host to Fort Devens, a major influence on the town. Fort Devens employs almost 8,000 people and has been a major factor in the local and regional economy. The pending closing of Fort Devens will have a profound impact on Ayer and the town is seeking to address and mitigate this impact as well as the effect of recent increases in poverty and decreases in population.