This talk presents several new results concerning the asymptotic behavior of large average submatrices of an $n \times n$ Gaussian random matrix. We begin by considering with the average and joint distribution of the (globally optimal) $k \times k$ submatrix having largest average value. We then consider submatrices with dominant row and column sums, which arise as the local optima of a useful iterative search procedure for large average submatrices. We present an analysis of the number $L_n(k)$ of locally optimal $k \times k$ submatrices, beginning with the asymptotic behavior of the mean and the variance of $L_n(k)$ for fixed k and increasing n. The principal result of the talk is a Gaussian central limit theorem for $L_n(k)$.