From the valley of the sloes
Derived from Old English elements 'sla' meaning sloe (a type of wild plum) and 'denu' meaning valley. It was originally a locational surname for someone living in a valley where sloe bushes grew.
Less common today
Sladen isn't in the latest US Top 1000. It last peaked at #6,034 in 2008.
American baseball player
US births per 5-year period, 1990βpresent (SSA data).