Monmouth Junction was created as the crossroads of three branches of the railway , the New York division of Pennsylvania Railroad , the Rocky Hill and the Jamesburg and Freehold . Monmouth Junction was created as the junction of three rail branches , the New York division of the Pennsylvania Railroad , the Rocky Hill and the Jamesburg and Freehold . New York was created as the junction of three rail branches , the Jamesburg division of the Pennsylvania Railroad , the Rocky Hill and the Monmouth Junction and Freehold .