The Great Eastern Railway (GER) was a pre-grouping British railway company, whose main line linked London Liverpool Street to Norwich and which had other lines through East Anglia. The company was grouped into the London and North Eastern Railway in 1923.

Formed in 1862 after the amalgamation of the Eastern Counties Railway and several other smaller railway companies the GER served Cambridge, Chelmsford, Colchester, Great Yarmouth, Ipswich, King's Lynn, Lowestoft, Norwich, Southend-on-Sea (opened by the GER in 1889), and East Anglian seaside resorts such as Hunstanton (whose prosperity was largely a result of the GER's line being built) and Cromer. It also served a suburban area, including Enfield, Chingford, Loughton and Ilford. This suburban network was, in the early 20th century, the busiest steam-hauled commuter system in the world.

The majority of the Great Eastern's locomotives and rolling stock were built at Stratford Works, part of which was on the site of today's Stratford International station and the rest was adjacent to Stratford Regional station. The GER owned 1,200 miles (1,931 km) of line and had a near-monopoly in East Anglia until the opening of the Midland and Great Northern Joint Railway in 1893 although there were a number of minor lines, such as the Mid-Suffolk Light Railway that stayed resolutely independent until after the grouping in 1923.

Between 1851 and 1854 the Eastern Counties Railway (ECR) under the chairmanship of David Waddington had negotiated arrangements to work most of the other railways in East Anglia resulting in a network of lines totalling 565 miles (909 km). Whilst Parliament favoured competition it was also aware that the ECR was constantly at war with its neighbours and whilst these working arrangements were approved there was a condition that a bill for full amalgamation was presented by 1861.

Waddington departed under a cloud in 1856 and was replaced by Horatio Love. By 1860 many shareholders were unhappy listing several grievances they saw as getting in the way of their dividend payments. These included continual conflict over working of other lines, suspicion and distrust of the joint committee, inadequate services to and from London, on-going litigation and law costs and a lack of progress on amalgamation.

By February 1862 the bill had its second reading and was then followed by a lengthy committee process where various parties petitioned against the bill. On 7 August 1862 the bill passed as the Great Eastern Railway Act 1862 (25 & 26 Vict. c. ccxxiii) and the Great Eastern Railway was formed by the amalgamation of the Eastern Counties Railway and a number of smaller railways (the Newmarket and Chesterford Railway, the Eastern Union Railway, and the Norfolk Railway).

Unsurprisingly the first GER board had a strong Eastern Counties flavour with Horatio Love in the chair and James Goodson the deputy chair. The board consisted of six former ECR directors with two Eastern Union Railway, two Norfolk Railway and one each from the Northern and Eastern Railway (still an independent body at this point) and East Anglian Railway.

Operational costs were high on the new railway and new sources of revenue needed quickly. Work at improving suburban services was put in hand and trains from London to Norwich speeded up to give businessmen and merchants more time to conduct their business. A new suburban line to Enfield Town via Seven Sisters was proposed as well as a new London terminus to replace an inadequate Bishopsgate. By August 1863 receipts were increasing and many of the pre-amalgamation disputes were being settled.