Roby incorporated in 1915, and its population grew to 801 in 1930 and 904 in 1940. The population peaked in 1950 with 1,040 people calling Roby and North Roby home, and 60 businesses. The city was plagued by insufficient water throughout its life and finally in 1953 during a long period of drought, water from Oak Creek Lake at Blackwell was piped in. By 1970, the population had fallen below 800 with 22 businesses in operation. It further declined to 616 in 1990 before rebounding to 673 in 2000, and as of the 2010 Census, the population had fallen to 643.