Lewis Dalvit founded the Beloit Civic Symphony in 1953. In 1971, it became the Beloit Janesville Symphony, performing concerts regularly in the two Rock County communities. The founder was succeeded by composer and Beloit College Professor Crawford Gates who served as music director until 15 years ago when Robert Tomaro assumed the post of music director and conductor. Dr. Tomaro is well known as a jazz and rock guitarist.  He has secured the Philharmonic's reputation, as a cultural mainstay of Rock County.

Since its founding, the Philharmonic has grown from 35 players to over 80.
The Philharmonic performs a dozen concerts each year including concerts each spring for thousands of school children and has recorded six CDs.

The Rock River Philharmonic Orchestra has grown to attract players from throughout Southern Wisconsin and Northern Illinois as it has developed from a community orchestra of volunteers to a professional organization and non-profit corporation that provides the Stateline area with outstanding cultural programs year-round.