Answer: Dundee United & Dundee
The two grounds are on opposite ends of Tannadice Street in Dundee, separated by a distance of around 200 yards. Dundee play at Dens Park, and United are based at Tannadice Park.
Dundee were formed in 1893 by the merger of two clubs, Dundee East End and Dundee Our Boys, and immediately joined the Scottish Football League. In 1899 they moved from their first home ground, Carolina Port, to Dens Park. Dundee United, who were known as Dundee Hibernian until 1923, have played at Tannadice Park since their foundation in 1909. They joined the Scottish Football League a year later.