Social network researchers are routinely faced with the boundary specification problem, namely, where to place limits on nodes that constitute a social network. The complexity of the issue varies; some networks are easily delineated, while others are not. For instance, if we were interested in exploring the relations among older people in an elder care home, then ‘residence’ would define actor membership. However, where a network exists with ambiguous, perhaps unstable, outer limits and its population proves tricky to access, significant challenges arise for the researcher. In this article, I consider ‘the boundary specification problem’ as it relates to an amorphous, ‘tricky-to-access’ population of cross-community youth leaders in North Belfast, Northern Ireland. This article will review current strategies and approaches for bounding social networks, assess the applicability of each and provide practical insights and extended ideas around delineating ambiguous, unstable, elusive structures composed of ‘tricky to access’ populations.