Alcántara is a municipality (pop. 1769) in the province of Cáceres, Extremadura, Spain, on the Tagus, near Portugal, with a bridge of six arches, 670 feet long and 210 feet high, built in honour of Trajan in 104. The Order of Alcantara , a religious and military order, was established in 1176 here, for defence against the Moors, and was suppressed in 1835.