On I-75 Northbound:  
Take Exit #56 at Stanley Avenue.  At the bottom of the exit ramp turn left (west) and go through two traffic lights.  **After the light at Keowee Street, the road takes a dogleg to the left.  Stay on Stanley until you reach the T-intersection with Helena Street.  Turn right (west) onto Helena Street. At the top of the knoll you will see the beige boathouse on the left and Five Rivers MetroParks Island Park on the right.  There are parking lots available on either side of Helena St., but boat trailer parking only on the boathouse (left/south) side. The other lots will be marked and wil have parking attendences for your convenience on race day.
On I-75 Southbound: 
Take the abrupt Exit #56B at Stanley Avenue WEST.  At the bottom of the ramp bear right and go through one traffic light at Keowee Street.  **Follow the above directions from this point.
From Downtown Dayton:
Take either Main Street or Riverside Drive north until you reach Helena Street.  Turn right (east) onto Helena Street and cross the Great Miami River on the Helena Street Bridge.  The boathouse is on the right (south) across from the Island Park Entrance.
Helena Street including the bridge will be closed to general traffic on regatta day starting at 9am.  General parking will be available on the levy, adjacent to Island MetroPark on the east side of the river.  It is not advised to park in the neighborhood on the west side of the river. 
REVIEW REGATTA PACKET for details on Parking