We regularly feature an Ohio city as part of our Ohio Community Spotlight series.
For 2026 we are expanding the series to focus not only on Ohio’s cities but the counties where they are located.
This month, we’re traveling to the state’s western edge as we look at Mercer County and it’s county seat - Celina!
Mercer County sits in Ohio’s western edge along the Indiana border. Home to about 42,500 residents, the county seat and largest city is Celina, located on the shores of Grand Lake St. Marys, one of Ohio’s best-known recreational destinations.
Long before European settlement, this area was part of the homelands and travel corridors of Indigenous peoples including the Miami, Shawnee, Wyandot, Delaware (Lenape), and other Native nations connected to the Ohio Country. Their history remains foundational to the region.
Mercer County was organized in 1824 and named for Revolutionary War physician and general Hugh Mercer. Celina became the county seat in 1839, replacing St. Marys, and remains the center of county government today.
The defining feature of the county is Grand Lake St. Marys. Constructed between 1837 and 1845 to supply water to the Miami & Erie Canal, it was once the world’s largest man-made reservoir and remains Ohio’s largest inland lake by area.
Grand Lake Saint Mary was one of the first projects addressed by Ohio’s H2Ohio program. Algal blooms had plagued the waterway, with the surrounding watershed being declared by the Ohio Department of Natural Resources as “in distress” in 2011. Work began in 2021 and treatments are making steady improvements to the region.
Celina was established in 1834 and grew alongside canal-era transportation and agriculture. Today, the city blends a walkable downtown, lakefront amenities, and strong community institutions with a population of roughly 11,000 residents.
One of Mercer County’s most surprising chapters is oil production. In the late 1800s, Grand Lake St. Marys hosted some of the world’s earliest offshore oil wells, with dozens of derricks standing directly in the lake.
Oil wells on Grand Lake, Ohio, after heavy rains in 1887 caused a rise in the lake level. Photo courtesy Joyce Alig, Oil & Gas Boom, Mercer County and midwestern Ohio.
Huffy Bikes, founded in nearby Miamisburg, once manufactured most of their bikes in Celina – the cities largest employer. However, deep financial problems in the mid-1990s forced the company to close the plant in 1998.
Agriculture remains a major economic driver. Mercer County consistently ranks among Ohio’s leading agricultural counties, supporting crop production, livestock operations, food processing, and agribusiness employment.
The lakefront is central to Celina’s identity. Lake Shore Park hosts festivals, concerts, recreation, and community events while providing public access to Grand Lake St. Marys for boating, fishing, and waterfront gatherings.
Mercer County is also known for its remarkably strong manufacturing base. Advanced manufacturing, precision machining, metal fabrication, and related industries provide thousands of jobs across the county.
Transportation helped build Mercer County. The Miami & Erie Canal connected communities to national markets in the 1800s, and today’s highway network continues to support regional commerce and industry.
Preserving the historic past is important for Celina and Mercer County. Back in 2021, local investors, with support from the county, the U.S. Department of Housing and Urban Development, and the Ohio Department of Development worked to restore the historic Lininger, or Old Millie building. A $250,000 grant supported the nearly $500,000 project.
Today, the building hosts a full service restaurant on the ground floor, with two floors of commercial space located above.
Photo by Dan Melograna/The Daily Standard
A company plans to buy the newly-rehabbed Lininger or Old Millie building in Celina. The LLC being formed plans to remodel the first floor and use it for mixed-use commercial purpose. At top is how it appears today and bottom is a postcard circa 1912.
Visitors often discover Mercer County through its festivals, lake activities, and small-town charm. Events throughout the year draw residents and tourists alike to Celina’s waterfront and downtown districts.
A local landmark worth seeking out is the Grand Lake St. Marys Lighthouse. Together with the lake, courthouse square, and historic downtown, it reflects the community’s connection to both history and recreation.
Mercer County and Celina demonstrate how a community can leverage natural resources, manufacturing strength, agricultural heritage, and quality-of-life investments to remain vibrant in the 21st century.
This thread was created with assistance from AI.
Cover Photo: Front view of four commercial buildings in Celina, Ohio. The buildings are contributing parts of the National Register-listed Main Street Commercial Historic District. Photo by Christopher L. Riley via Wikimedia Commons.