 Regionalization techniques have become increasingly important in the field of hydrology as they allow for the prediction of streamflow in un-gaged catchments. Two main approaches exist, one which estimates parameters of streamflow statistics, such as flood quantiles, and another which uses a rainfall runoff model to simulate continuous streamflow or estimate continuous streamflow without using a model. Most methods used to estimate continuous streamflow for un-gaged catchments can also be applied to estimating streamflow statistics. This paper reviews both distance-based and regression-based methods, discussing their advantages and disadvantages. This article is authored by Wahee, Abartisi, and EZ.