We observe magnetic trapping of atomic nitrogen ($^{14}$N) and cotrapping of ground state imidogen ($^{14}$NH, $X^3\Sigma^-$). Both are loaded directly from a room temperature beam via buffer gas cooling. We trap approximately $1 \times 10^{11}$ $^{14}$N atoms at a peak density of $5 \times 10^{11}$ cm$^{-3}$ at 550 mK. The 12~+5/$-3$ s $1/e$ lifetime of atomic nitrogen in the trap is limited by elastic collisions with the helium buffer gas. Cotrapping of $^{14}$N and $^{14}$NH is accomplished, with $10^{8}$ NH trapped molecules at a peak density of $10^{8}$ cm$^{-3}$. We observe no spin relaxation of nitrogen in collisions with helium.