  We report the low temperature magnetic properties of Ce$_2$Sn$_2$O$_7$, a
rare-earth pyrochlore. Our susceptibility and magnetization measurements show
that due to the thermal isolation of a Kramers doublet ground state,
Ce$_2$Sn$_2$O$_7$ has Ising-like magnetic moments of $\sim1.18$
$\mu_\mathrm{B}$. The magnetic moments are confined to the local trigonal axes,
as in a spin ice, but the exchange interactions are antiferromagnetic. Below 1
K the system enters a regime with antiferromagnetic correlations. In contrast
to predictions for classical $\langle 111 \rangle$-Ising spins on the
pyrochlore lattice, there is no sign of long-range ordering down to 0.02 K. Our
results suggest that Ce$_2$Sn$_2$O$_7$ features an antiferromagnetic liquid
ground state with strong quantum fluctuations.
