Regular Points of a Subcartesian Space We discuss properties of the regular part $S_{\operatorname{reg}}$ of a subcartesian space $S$. We show that $S_{\operatorname{reg}}$ is open and dense in $S$ and the restriction to $S_{\operatorname{reg}}$ of the tangent bundle space of $S$ is locally trivial. Keywords:differential structures, singular and regular pointsCategory:58A40