Update: Fox News just projected Mitt Romney's victory as well.
With 99% of precincts reporting and over one million votes counted, Mitt Romney has won the Ohio Republican Primary by 12,000 votes as of 12:30 eastern time.
County-by-county results show all Santorum strongholds have reported at, or near 100%, while the 2 remaining counties with incomplete results support Romney by over six percentage points each.
This caps one amazing night in the Buckeye State, as Mitt Romney came from ten points down to win Ohio in the final week of campaigning and did so with almost 80,000 more voters participating then in 2008 when McCain and Huckabee were fighting at the tail end of the nomination process.
Romney - 451,972 (38%)
Santorum - 439,932 (37%)
Gingrich - 173,797 (14.6%)
Ron Paul - 110,289 (9.3%)