  We demonstrate a blue-detuned magneto-optical trap (MOT) of a polyatomic
molecule, calcium monohydroxide (CaOH). We identify a novel MOT frequency
configuration that produces high spatial compression of the molecular cloud.
This high compression MOT achieves a cloud radius of $59(5)~\mu\text{m}$ and a
peak density of $8(2) \times 10^8~\text{cm}^{-3}$, the highest reported density
for a molecular MOT to date. We compare our experimental studies of
blue-detuned MOTs for CaOH and compare with Monte-Carlo simulations, finding
good agreement.
