ΔE 15.1, loose: different enough that you should pick on purpose. US Earth Red is noticeably lighter, warmer than Oxide Brown Dark.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). US Earth Red is noticeably lighter, warmer than Oxide Brown Dark.
The same difference applies the other way round: Oxide Brown Dark is noticeably darker, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Oxide Brown Dark on the colour wheel See US Earth Red on the colour wheel
All matches: Oxide Brown Dark equivalents · US Earth Red equivalents