Read Ezekiel 42:20 Using Other Translations
He measured it by the four sides: it had a wall round about, five hundred reeds long, and five hundred broad, to make a separation between the sanctuary and the profane place.
He measured it on the four sides. It had a wall around it, cubits long and cubits broad, to make a separation between the holy and the common.
So the area was 875 feet on each side with a wall all around it to separate what was holy from what was common.