Originally, Bladen was a vast territory with indefinite northern and western boundaries. Reductions in its extent began in 1750, when its western part became Anson County. In 1752 the northern part of Bladen County was combined with parts of Granville County and Johnston County to form Orange County. In 1754 the northern part of what was left of Bladen County became Cumberland County. In 1764 the southern part of what remained of Bladen County was combined with part of New Hanover County to form Brunswick County. In 1787 the western part of the now much smaller county became Robeson County. Finally, in 1808 the southern part of Bladen County was combined with part of Brunswick County to form Columbus County.
Cumberland to the north, Sampson on the northeast, Pender on the southeast, Columbus to the south and Robeson on the west.