The first section was opened by the Eastern Counties Railway (ECR) on 20 June 1839 from the London end at Devonshire Street to Romford, extended on 1 July 1840 to Bishopsgate (London end) and Brentwood. The Northern and Eastern Railway (N&ER) opened its first section from that line at Stratford to Broxbourne on 15 September 1840, and to Harlow in 1841; though it remained a separate entity, its line was leased to the ECR from 1 January 1844. A branch from Broxbourne to Hertford opened in 1843.