Crystallographic analysis shows that UCuSn does not form in the hexagonal CaIn2 structure as reported previously, but is an ordered ternary compound and forms in an orthorhombic structure (space group: P21cn). Bulk and neutron-diffraction measurements reveal that UCuSn orders antiferromagnetically below 62 K. At 4.2 K, high-field magnetization reveals a complex magnetization process with two metamagnetic transitions. Furthermore, bulk investigations show an additional anomaly at 25 K, but a smooth temperature dependence of various magnetic peaks down to the lowest temperature gives no evidence for a second magnetic transition. Possible scenarios responsible for the drastic changes in the electronic properties around 25 K are discussed.