Which preposition to use with pamunkey

at Occurrences 1%

Crossing the Pamunkey at Hanovertown, after a rapid night-march, General Grant sent out a force toward Hanover Court-House to cut off Lee's retreat or discover his position.

below Occurrences 1%

I was to communicate with General Franklin, whose division on this day ought to have landed on the south bank of the Pamunkey below White House for the purpose of cutting off the Confederates' retreat.

toward Occurrences 1%

General Grant found his whole programme reversed, and, on the night of the 26th, silently withdrew and hastened down the north bank of the Pamunkey toward Hanovertown preceded by the cavalry of General Sheridan.

Which preposition to use with  pamunkey