We developed a transect-to-transect stochastic model of stream width and pools. The model included Markov chains for transect-to-transect transitions among pools, nonpools, and part pools, a two-parameter beta distribution for pool fraction when the transect is a partial pool, and a two-parameter gamma distribution to model standardized widths. The model accurately reproduced the mean and standard deviation of both width and transect-based measures of pool area. However, the model smoothed the distributions thereby reducing the skewness of the observed data. The physical tendency for streams to have very few transects that are almost, but not totally, all pool or nonpool implies that stochastic models based on continuous distributions will have more density in the tails than observed on the stream. The model represented odd-shaped empiric distributions of pool area which indicates it is very flexible and can accurately model a variety of streams.¿ 1997 American Geophysical Union