Eastern Counties 6 was an English level 13 Rugby Union league with teams from Cambridgeshire, Essex, Norfolk and Suffolk taking part. Promoted teams used to move up to Eastern Counties 5 and, as this was the lowest tier league in the Eastern Counties divisions, there was no relegation. After just four seasons Eastern Counties 6 was cancelled at the end of the 1991–92 campaign.
^Due to the cancellation of Eastern Counties 6 at the end of the season, champions Witham were promoted two divisions up to Eastern Counties 4.
^Due to the cancellation of Eastern Counties 6 at the end of the season, runners up Burnham-on-Crouch were also promoted two divisions up to Eastern Counties 4. The other eight teams in the division went into Eastern Counties 5.