The simple plant location problem is a well-studied problem in combinatorial optimization. It is one of deciding where to locate a set of plants so that a set of clients can be supplied by them at the minimum cost. This problem often appears as a subproblem in other combinatorial problems. Several branch and bound techniques have been developed to solve this problem. In this paper we present some techniques that enhance the performance of branch and bound algorithms. Computational experiments show that the new algorithms thus obtained generate less than 60% of the number of subproblems generated by branch and bound algorithms, and in certain cases require less than 10% of the execution times required by conventional branch and bound algorithms.