  We use mass formulas to construct minimal parabolic Eisenstein congruences
for algebraic modular forms on reductive groups compact at infinity, and study
when these yield congruences between cusp forms and Eisenstein series on the
quasi-split inner form. This extends recent work of the first author on weight
2 Eisenstein congruences for GL(2) to higher rank.
  Two issues in higher rank are that the transfer to the quasi-split form is
not always cuspidal and sometimes the congruences come from lower rank (e.g.,
are "endoscopic"). We show our construction yields Eisenstein congruences with
non-endoscopic cuspidal automorphic forms on quasi-split unitary groups by
using certain unitary groups over division algebras. On the other hand, when
using unitary groups over fields, or other groups of Lie type, these Eisenstein
congruences typically appear to be endoscopic. This suggests a new way to see
higher weight Eisenstein congruences for GL(2), and leads to various
conjectures about GL(2) Eisenstein congruences.
  In supplementary sections, we also generalize previous weight 2 Eisenstein
congruences for Hilbert modular forms, and prove some special congruence mod p
results between cusp forms on U(p).
