The distribution and extent of lunar swirls

•Low UV/Vis ratios and moderate to high albedo most clearly distinguish swirls.•Swirls are found in two large geographic groups and a host of smaller patches.•Swirl color properties are consistent with a lack of submicroscopic-iron-bearing agglutinates.•Swirl color varies with distance from Copernican and some Eratosthenian craters.