Abstract. We prove formulas for power moments for point counts of elliptic curves over a finite field k such that the groups of k-points of the curves contain a chosen subgroup. These formulas express the moments in terms of traces of Hecke operators for certain congruence subgroups of SL 2 (Z). As our main technical input we prove an Eichler-Selberg trace formula for a family of congruence subgroups of SL 2 (Z) which include as special cases the groups Γ 1 (N ) and Γ(N ). Our formulas generalize results of Birch and Ihara (the case of the trivial subgroup, and the full modular group), and previous work of the authors (the subgroups Z/2Z and (Z/2Z) 2 and congruence subgroups Γ 0 (2), Γ 0 (4)). We use these formulas to answer statistical questions about point counts for elliptic curves over a fixed finite field, generalizing results of Vlǎduţ, Gekeler, Howe, and others.