The wave energy resource is characterized and assessed for US wave climates to evaluate project opportunities, constraints and risks for wave energy conversion (WEC) projects. Partitioned wave parameters generated from a 30-year WaveWatch III model hindcast are used to estimate the total wave energy potential as an annual available energy (AAE), which is a theoretical annual energy production per unit energy capture length without considering energy conversion losses. The distribution of AAE by peak period, wave direction, month, and year are quantified using seven summary statistics (aka resource parameters, metrics or indices), including peak period spread, AAE-weighted period, AAE-directionality coefficient, direction of maximum directionally resolved AAE, and inter-annual and seasonal temporal variability. Additionally, extreme wave heights at 50-year recurrence intervals, Hs(50), and the relative risk ratio, Hs(50)/Hs(mean), are presented as indices of project risk. Geographical distributions of the and these additional resource attributes delineate distinct wave energy resource regions within US coastal waters, where different opportunities, constraints and risks may influence WEC conceptual design, project development and regional energy planning.