Alcanena is a Portuguese town and municipality of Ribatejo in Santarém District. The population in 2011 was 13,868, in an area of 127.33 km²…Alcanena is a Portuguese town and municipality of Ribatejo in Santarém District. The population in 2011 was 13,868, in an area of 127.33 km². The current Mayor is Rui Anastácio and the president of the Municipal Assembly is Silvestre Pereira. The municipal holiday is Ascension Day.