There is increasing interest in measuring the overlap and/or incremental reach of cross-media campaigns. The direct method is to use a cross-media panel but these are expensive to scale across all media. Typically, the cross-media panel is too small to produce reliable estimates when the interest comes down to subsets of the population. An alternative is to combine information from a small cross-media panel with a larger, cheaper but potentially biased single media panel. In this article, we develop a data enrichment approach specifically for incremental reach estimation. The approach not only integrates information from both panels that takes into account potential panel bias, but borrows strength from modeling conditional dependence of cross-media reaches. We demonstrate the approach with data from six campaigns for estimating YouTube video ad incremental reach over TV. In a simulation directly modeled on the actual data, we find that data enrichment yields much greater accuracy than one would get by either ignoring the larger panel, or by using it in a data fusion.