Limited, but still (5 October 1813)
While we usually date the abolition of slavery in Mexico to 1829 (when even the carve-out for Tejas’ slave-owning Anglo population was abolished), the insurgents during the Independence struggle of 1810-20 were liberating slaves in the territory they held. Informally, until… having formed a provisional government in Chilpancingo, Morelos … as acting president… decreed all slaves in the regions they controlled free.
““Because slavery and everything that smacks of it must be removed from America, I command that the Provincial Mayors and other magistrates ensure that as many slaves as are left are released, and that the Natives who form Towns and Republics hold free elections, presided over by the Parish [communal or sub-regional administration] and Territorial Judge who will not coerce them to a certain person”; points out this part of the decree.”
The Mex Files 