By its very nature, the production of siliciclastic sediment destroys much of the direct evidence of its source region, so geoscientists are left with indirect tools to assess metrics such as catchment basin size. In this paper, Davidson and Hartley relate the areal extent of existing large (> 30 km in length) distributive fluvial systems (DFS) formed in endorheic basins to contributing drainage basin area. Regression analyses indicate a strong positive relationship between drainage area and DFS area; additionally, drainage basin relief influences sediment supply in terms of volume or caliber, which in turn affects the depositional gradient of the DFS surface and resultant channel planform. Application of these regression relationships to examples in the rock record shows that DFS area can be used as a proxy to predict the surface area of fluvially transported sediment deposited in a sedimentary basin from the contributing catchment. The modern regression relationships suggest a measurable link between source and sink in the sedimentary rock record, and provide a potential tool for more accurate prediction of preserved fluvial architecture within basin-scale climatic and tectonic contexts.