▁of ▁the ▁Pot om ac ▁River ▁in ▁Northern ▁Virginia , ▁where ▁it ▁serves ▁as ▁part ▁of ▁the ▁boundary ▁between ▁Fair f ax ▁and ▁Prince ▁William ▁count ies . ▁The ▁river ▁is ▁ ▁long , ▁and ▁its ▁waters hed ▁covers ▁about ▁. ▁It ▁is ▁formed ▁by ▁the ▁confl u ence ▁of ▁Broad ▁Run ▁and ▁C ed ar ▁Run ▁in ▁Prince ▁William ▁County ; ▁Bull ▁Run , ▁which ▁forms ▁Prince ▁William ▁County ' s ▁boundary ▁with ▁L oud oun ▁and ▁the ▁nor ther ly ▁part ▁of ▁Fair f ax ▁count ies , ▁enters ▁it ▁east - s out heast ▁of ▁Man ass as , ▁as ▁the ▁Occ o qu an ▁turns ▁to ▁the ▁sout heast . ▁It ▁reaches ▁the ▁Pot om ac ▁at ▁Bel mont ▁Bay . ▁The ▁Occ o qu an ▁River ▁is ▁part ▁of ▁the ▁Ch es ape ake ▁Bay ▁waters hed . ▁The ▁name ▁Occ o qu an ▁is ▁derived ▁from ▁a ▁Do eg ▁Alg on qu ian ▁word ▁translated ▁as ▁" at ▁the ▁end ▁of ▁the ▁water ". ▁ ▁The ▁river ▁is ▁a ▁scen ic ▁area , ▁and ▁several ▁local ▁high ▁schools ▁and ▁colleg es ▁use ▁the ▁river ▁for ▁the ▁sport ▁of ▁row ing . ▁ ▁Ge ograph ers , ▁for em ost ▁Harm ▁de ▁B lij , ▁defined ▁the ▁river ▁as ▁the ▁most ▁apt ▁border ▁between ▁the ▁American ▁North ▁and ▁American ▁South . ▁Wolf ▁Run ▁Sho als ▁was ▁an ▁important ▁crossing ▁point ▁on ▁the ▁Occ o qu an ▁between ▁Alexand ria ▁and ▁Richmond ▁during ▁the ▁ 1 8 th ▁and