I investigated peatland water table elevation responses to large precipitation events and long precipitation-free periods for a fen, poor fen, and bog, and pore water chemistry trends in a fen boundary zone, in northern Minnesota. Water table change compared to both precipitation and dry periods was slower in the fen than the poor fen or bog, a response attributed to connections between the fen and the regional groundwater aquifer. Water table change compared to larger dry periods remained consistent over a 51-year period and among peatlands. Calcium-silicon ratios in fen pore water were collected along transects perpendicular to the fen boundary. Larger calcium-silicon ratios at edge of the fen were interpreted as originating from a regional aquifer source, with minimal influence from vegetative calcium uptake and upland subsurface runoff. The extent of the fen-upland boundary zone was demarcated where calcium-silicon ratios matched average fen and stream outlet calcium-silicon ratios.