SR 307 was original certified in 1933, it was routed between Madison and SR 45 along current State Route 84. In 1934 SR 307 swapped alignments with SR 84.
SR 307 was initially certified in 1933; it was routed between Madison and SR 45 along current State Route 84. In 1934, the alignment of SR 307 changed to match that of SR 84.