Mercer County, Ohio Business Directory & Community Resources
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View the 2025 U.S. Census demographic profile for Mercer County
Mercer County — County Seat: Celina
2026 Population Estimate: 42,954 | Official Website: https://www.mercercountyohio.gov/
Mercer County is a prosperous western Ohio county with Celina as its county seat on the shores of Grand Lake St. Marys — the largest inland lake in Ohio and historically the largest man-made lake in the world when it was completed in 1845 to feed the Miami and Erie Canal. The county has one of the strongest agricultural economies in Ohio, anchored by a remarkably productive dairy and hog industry. The county's German Catholic heritage is pervasive and visible in its beautifully maintained communities, stunning Gothic churches, and strong civic traditions. Major employers include Honda of America Mfg. (Anna Engine Plant in neighboring Auglaize County is a major draw for this county's workforce), and Celina Insurance Group. Wright State University – Lake Campus in Celina provides higher education. Grand Lake St. Marys attracts boaters, anglers, and summer vacationers throughout the season, and the lake is surrounded by charming lakefront communities.
▸ Key Industries & Major Employers
Agriculture (poultry and hog production), food processing, and manufacturing.
Major employers include Mercer County Community Hospital, Tri-Star Trust, Superior Industries International, and agricultural processing operations. Mercer County is consistently one of Ohio's top agricultural counties—particularly for hogs, poultry, and eggs—and hosts major food processing operations including a Tyson Foods supplier network.
▸ Notable Economic Development Initiatives
The Mercer County Economic Development office focuses on agricultural processing and food industry investment. The Grand Lake St. Marys area supports a small but active tourism economy. Ohio's agricultural investment tax credits support local farming operations. Workforce training programs at local career centers focus on ag-related manufacturing skills.
▸ Infrastructure & Investment Highlights
SR-29 and US-127 are primary corridors. Grand Lake St. Marys supports recreational boating. Rural broadband expansion is ongoing. Agricultural infrastructure—grain elevators, livestock processing—is distributed across the county.
