Acid deposition has been implicated as a factor contributing to the depletion of base cations in forest soils of eastern North America. Reductions in S emissions in this region during the past 25 years have resulted in declines in precipitation SO₄^- deposition at the Turkey Lakes Watershed, located on the Canadian Shield in central Ontario. While declining inputs of atmospheric acids should reduce soil acidification and cation leaching rates, natural production of NO₃^-, the release of adsorbed SO₄^- and soil base cation content could influence long-term trends. The Turkey Lake site supports a mature sugar maple dominated tolerant hardwood forest with acidic podzol soils that have developed in shallow glacial till deposits. In spite of similarity in profile morphology across the 10 km² research watershed there was a large range in the soil reserves of exchangeable base cations. Our objectives were to examine how solution chemistry in soils with varied base contents responded to changing deposition and to determine if there were detectable changes in soil base reserves at the Turkey Lake Watershed over a 20-year time period. We measured ion concentrations in forest-floor and mineral soil percolate during periods of high and low deposition at two stands in the watershed that represented soils with different base saturations (30 % and 10 % in the B horizon). Base cation contents were determined for mineral soils sampled from the same two stands in the mid-1980’s and again in the mid-2000’s. Archived soil samples were used to compare laboratory methodologies over the study period.