Lake size is a strong control on lake function and on how lakes interact with the environment. For example, lake size is related to carbon burial rates in lake sediments. Lake size distribution (the number of small, medium, and large lakes per unit area) can be used to extrapolate lake function to landscapes at local, regional and global scales. This research examined the utility of using radar satellite imagery (ALOS PALSAR) and existing spatial data (CanVec) for the construction of a new Canadian lake database, which was then used to estimate carbon accumulation in Canadian boreal lake sediments. The capability of ALOS PALSAR images for classifying lakes from eight pilot regions across Canada was assessed by direct comparison to existing CanVec data. The PALSAR lake classification differed between -1.8% to 18.0% for overall lake area and -56.0% to 196.0% for overall lake count compared to CanVec. The wide range in difference can be explained by limitations in resolution, classification method, and how a lake was defined. While the temporal resolution of PALSAR was superior, it did not provide better spatial resolution and accuracy than existing datasets. PALSAR’s utility therefore is in short term change determination. Consequently, CanVec was used to construct the final database describing lake distribution in Canada, resulting in over 13.2 million features with a total area of almost 1.2 million km2. Lake database results suggest that the scaling rules used in previous studies to estimate the number of very small lakes regionally and globally have limits. The use of real lake data allowed for a better understanding of regional differences in lake distribution across Canada that was not possible with scaling rule approaches. Estimates of carbon accumulation in boreal Canada lake sediments based on the new CanVec lake distribution and literature-based accumulation rates ranged from 1.65 and 2.34 Mt C yr-1, or roughly equal to the carbon emissions of 300,000-450,000 cars per year. Similarly, it would require only 36 years for Canada’s total annual emissions to account for all the carbon accumulation in Canadian boreal lakes over the Holocene (last 10,000 years). Thematic products derived from the lake database suggest that number of lakes is more important than the distribution of small, medium and large lakes when estimating carbon accumulation in the lake sediments of boreal Canada. / Graduate