Between 1674 and 1702, in the early part of New Jersey's colonial period, the border between West Jersey and East Jersey ran diagonally across the middle part of the state. The Keith Line, as the demarcation is known, ran through the center of what is now Mercer County. This border remained important in determining ownership and political boundaries until 1745. Remnants of that division are seen today, notably as the Hunterdon-Somerset, Ocean-Burlington, and Monmouth-Burlington county lines. The division of the two provinces was cultural as well as geographical.