This is a good place for the history of Men's College Lacrosse in Ohio. The easiest way to break it down would be to divide it into two sections. Before 1993 and after 1993.
Before 1993 there were so few teams west of PA that they all played in the same conference regardless of division. The Midwest Lacrosse Association (MLA). The Ohio teams in that Conference were Ohio State along with six D3 teams,. To borrow an NHL term I will refer to them as the "Original Six"; Denison, Ohio Wesleyan, Kenyon, Oberlin, Wooster and Wittenberg. The Original Six are still going strong today in the North Coast Conference. Other teams came and went during this era including Ohio U, Bowling Green, Akron, Cincinnati, Ashland (D2), Mt Union and Marietta (D3).
Kenyon started playing in 1948. Oberlin had a team by then, although I'm not sure if they started that year or before as they don't have their history on their website. Denison and Ohio State went varsity in 1953. OWU in 1956. Wittenberg and Wooster came on a little later than the others, but both had teams by 1971.
Today there are only 2 D1 teams, OSU and Cleveland State. There are only two D2 teams, Lake Erie and Walsh, neither of which OSU has ever played. At the D3 level College Lacrosse has absolutely exploded in the last 10 years or so, expanding from the Original Six to a whopping 19 teams including the entire OAC. The North Coast has 7 Ohio teams; The Original Six plus Hiram along with a pair of Indiana schools. The entire OAC has gone varsity starting with Otterbein in 2010. Marietta was the final hold out and they will start playing this year. Additionally Mt St Joe's and Franciscan have varsity teams. In fact there are only three D3 schools in Ohio that don't have varsity Lacrosse teams at this point; Case Western, Defiance and Bluffton.