Celina ( /səlaɪnə/ sə-ly-nə) is a city in and the county seat of Mercer County, Ohio, United States. The population was 10,303 at the 2000 census. Celina is situated on the western shores of Grand Lake St. Marys.
Celina was founded in 1834 in a swampy, wooded area that had to be drained and cleared before it could be settled. What remained was a level town surrounded by rich farm fields. When one of the town's founding fathers Josh Evers was traveling through New York state to get the town plat lithographed, he came across the town of Salina situated on the edge of Onondaga Lake near Syracuse. Noting the similarity between Salina and the newly founded settlement in Ohio, he named the new town Celina. The spelling was changed to avoid confusion at the post office, or so the story is told from past legends. Another legend has it that the spelling was changed because in Salina, NY, Main Street is oriented east-west (also Market Street is oriented north-south), where in Celina, OH, Main Street is oriented north-south (and Market Steet is oriented east-west).
Celina grew slowly after its founding in 1834. In 1880, only 1,346 people resided in the community, but over the next decade, Celina’s population nearly doubled to 2,684 inhabitants. The primary reason for this population growth was the discovery of oil and natural gas deposits during the 1880s. In 1886, Celina contained three newspaper offices, five churches, and two banks. Numerous manufacturing establishments existed in the community, most of which provided services or products to farmers in the surrounding countryside. This has held true throughout the twentieth century. In 2000, Celina was the largest municipality in Mercer County, with a population of 10,303 people.