SELECT MIN("Area km 2") FROM table_60610 WHERE "Official Name" = 'southampton' AND "Population" > '1,601'
Which Area km 2 has an Official Name of southampton, and a Population larger than 1,601?
CREATE TABLE table_60610 (
    "Official Name" text,
    "Status" text,
    "Area km 2" real,
    "Population" real,
    "Census Ranking" text
)