Mercer County Courthouse is located at 5 Diamond Street, Mercer PA 16137; phone: 724‑662‑3800.
Formed March 12, 1800; named for General Hugh Mercer of the Revolutionary War, who was killed in the Battle of Princeton; rolling land, well watered with springs and creeks; coal underlying one-fourth of land in the county; chief industries are iron, steel, and agriculture; early settlers were Scotch-Irish. In 1812, Mercer County people were frequently called upon to aid in defense of Erie; the whole county would be aroused in a day by runners; in a few hours most of the men, whether militia or volunteers, would be on the march; one call came on Sunday, while service was being held in the courthouse; the sermon was suspended, news announced, benediction given, and immediate preparation for march commenced; at another time, news of threatened invasion came in the middle of grain harvest; the response was immediate, only one old man was left in the town.
In Year 2005 ... 
- ....Mercer County maintains a diverse array of urban,
suburban and rural community types, yet has grown in a
manner that respects the rural character and provides a high
quality of life for all residents.
- the County has embraced the concept of "smart growth,"
as evidenced through guiding policies, strong leadership, and
- existing towns continue to invest in their core districts
and continue to grow in areas that are suitable for
development. Municipalities plan and implement jointly to
save costs and provide high-quality services as a region.
- economic opportunities are flourishing within the County,
creating new jobs and attracting new residents. Sustainable
forestry and agriculture are strong economic components of
the rural landscape and economy.
- the County provides many recreational, cultural, and
educational opportunities for residents and visitors through
sound planning and program development.
- young persons are staying or moving to the region to take
advantage of abundant entertainment and recreation
opportunities, as well as safe, affordable neighborhoods well-served
by water/sewer and telecommunications utilities.
- existing residents and newcomers enjoy many
opportunities to live, work, learn, retire, and play among the
County's strong community fabric and friendly people.
- Archambault, A. Margaretta, ed., A Guide Book of Art, Architecture, and Historic Interests in Pennsylvania, John C. Winston Company, Philadelphia, 1924
- Mercer County Comprehensive Plan Executive Update, 2005, www.mcrpc.com, accessed August 2009
- Aurora County Courthouse
- Lincoln House
- Raesly House
- Sweep Hotel
- Smith, William P., House
- Hilton House
- Hofmeister House
- South Dakota Department of Transportation Bridge No. 02-007-220
- South Dakota Department of Transportation Bridge No. 02-012-240