  As part of the HST/STIS GRB host survey program we present the detection of
three faint gamma-ray burst (GRB) host galaxies based on an accurate
localisation using ground-based data of the optical afterglows (OAs). A common
property of these three hosts is their extreme faintness. The location at which
GRBs occur with respect to their host galaxies and surrounding environments are
robust indicators of the nature of GRB progenitors. The bursts studied here are
among the four most extreme outliers, in terms of relative distance from the
host center, in the recent comprehensive study of Bloom et al. 2002. We obtain
a revised and much higher probability that the galaxies identified as hosts
indeed are related to the GRBs (P(n_chance)=0.78, following Bloom et al. 2002),
thereby strengthening the conclusion that GRBs are preferentially located in
star-forming regions in their hosts. Apart from being faint, the three hosts
consist of multiple structures, indicative of merging and active
star-formation. For one of the hosts, GRB 980329, we estimate a photometric
redshift of z~3.5.
