Interdisciplinary and unconventional research methods offer important insights into geomorphic, hydrologic and hydroclimatologic characteristics of large floods that are often difficult or impossible to resolve in the framework of conventional flood analysis. Four detailed studies of modern floods, historical floods, and paleofloods in western and central Arizona demonstrate the benefits of analyzing recent and historical extreme floods within the conceptual framework of paleoflood hydrology and flood hydroclimatology. Analysis of the hydroclimatological and paleohydrological context of extreme flooding in Arizona during the winter of 1993 provides a detailed analog to the likely climatic, meteorologic, and hydrologic conditions associated with the largest events in the regional paleoflood record. Investigation of the distribution of relict high-water evidence from extreme floods on the lower Verde River in 1993 improves the accuracy of the river's paleoflood record and reveals interesting hydrological phenomena of extreme floods in the Verde River Basin. A multidisciplinary study of the extraordinarily large Bronco Creek, Arizona, flood of August 1971, shows the original estimate to be significantly overestimated because of complex flow behavior of an extreme flood and the related dynamic morphological response of a high-gradient alluvial channel. The approach to this study is a template for similar analyses of extreme floods and extraordinary flood discharge estimates. A similar, more comprehensive application of paleoflood research methods is demonstrated by the compilation of a detailed regional chronology of flash-flooding in small desert drainage basins (7-70 km²) in western Arizona. The occurrences of large, recent and historical floods were documented with nearly annual resolution, and a 1200-year regional paleoflood record was compiled. Comparison of these records to conventional regional flood-frequency relations indicates that the regional equations are probably inaccurate because of data limitations. The study presents a viable approach to developing a quantitative assessment of regional flood frequency in areas with no conventional data on real floods. The results of each of these studies extend the spatial and temporal scope of the paleoflood and historical flood record of the lower Colorado River Basin and provide further support for the concept of a regional upper limit to flood peak magnitudes.