simple SQL clipping for four sections of US: Alaska, contiguous states, Hawaii, and Puerto Rico & the USVI.

query.sql

SELECT * FROM table WHERE (
  (
    lat > 51 AND lat < 71.5
    AND ((
        lon > -180 AND lon < -129
      ) OR (
        lon > 172 AND lon < 180
    ))
  ) OR (
    lat > 24 AND lat < 49.5
      AND lon > -125 AND lon < -66.5
  ) OR (
    lat > 18.5 AND lat < 29
      AND lon > -178 AND lon < -155
  ) OR (
    lat > 17.5 AND lat < 19
      AND lon > -68 AND lon < -64
  )
);