  We propose a general method for mapping the extinction in dense molecular
clouds using 2MASS near-infrared data. The technique is based on the
simultaneous utilization of star counts and colors. These two techniques
provide independent estimations of the extinction and each method reacts
differently to foreground star contamination and to star clustering. We take
advantage of both methods to build a large scale extinction map (2.5 x 2.5
degrees) of the North America-Pelican nebulae complex. With Ks star counts and
H-Ks color analysis the visual extinction is mapped up to 35 mag. Regions with
visual extinction greater than 20 mag account for less than 3% of the total
mass of the cloud. Color is generally a better estimator for the extinction
than star counts. Nine star clusters are identified in the area, seven of which
were previously unknown.
