  We report on the Stark deceleration and electrostatic trapping of $^{14}$NH
($a ^1\Delta$) radicals. In the trap, the molecules are excited on the
spin-forbidden $A ^3\Pi \leftarrow a ^1\Delta$ transition and detected via
their subsequent fluorescence to the $X ^3\Sigma^-$ ground state. The 1/e
trapping time is 1.4 $\pm$ 0.1 s, from which a lower limit of 2.7 s for the
radiative lifetime of the $a ^1\Delta, v=0,J=2$ state is deduced. The spectral
profile of the molecules in the trapping field is measured to probe their
spatial distribution. Electrostatic trapping of metastable NH followed by
optical pumping of the trapped molecules to the electronic ground state is an
important step towards accumulation of these radicals in a magnetic trap.
