The Division was a formation created during wartime.

On 15th August 1914, orders were issued to separate the 'home service' men from those who had undertaken to serve overseas, with the intention of forming reserves made up of those who had not so volunteered. On 31st August, authority was given to establish a 2nd-Line Division for each of the 1st-Line where more than 60% of the men had volunteered. These Divisions were formed from late 1914, although the permissible strength of a 2nd-Line unit was only half of the normal establishment. This was raised to full establishment early in 1915, after which many of them were sent overseas, with some playing important parts in the fighting. On 24th November 1914, it was decided to replace each overseas-service unit which proceeded abroad with its reserve unit; and directly this happened, a second reserve unit, or 3rd-Line, would be formed. Several of the newly-formed Second-Line units joined the West Lancashire Division, replacing original units which had gone to France independently. The remainder formed up into the 2nd West Lancashire Division, which was redesignated as the 57th in August 1915.

The Second-Line TF units were possibly the worst-off of all as regards equipment and other supplies, especially artillery. It was not until November 1915 that Lee-Enfield .303" rifles were received. Artillery came a month later, and Lewis guns only in February 1916. The complete Division moved to France between 7th and 22nd February 1917, and thereafter served on the Western Front, taking part in the following:

The Second Battle of Passchendaele (eighth phase of the Third Battle of Ypres)

The Battle of the Scarpe (first phase of the Second Battles of Arras 1918)

The Battle of Drocourt-Queant (second phase of the Second Battles of Arras 1918)

The Battle of the Canal du Nord (third phase of the Battles of the Hindenburg Line)

The Battle of Cambrai 1918 (sixth phase of the Battles of the Hindenburg Line)

In the above action, the Division helped capture Cambrai

The Final Advance in Artois

In the above action, the Division helped occupy Lille. After the Armistice, and a move to assist clearance near Arras, demobilisation happened quickly. By 23rd March 1919, most units were down to cadre strength, although it was not until 4th July 1919 that the last artillery details embarked at Dunkirk and the 57th Division ceased to exist.

170th (2nd North Lancs) Brigade

2/5th Bn, the King's Own (joined April 1915)

1/5th Bn, the Loyal North Lancs (joined June 1918)

2/4th Bn, the Loyal North Lancs (joined April 1915)

2/5th Bn, the Loyal North Lancs (joined April 1915, left February 1918)

4/5th Bn, the Loyal North Lancs (joined April 1915, absorbed by 1/5th Bn February 1918)

170th Brigade Machine Gun Company (joined February 1917, moved into 57 MG Bn 1 March 1918)

170th Trench Mortar Battery (joined February 1917)

171st (2nd Liverpool) Brigade

1/8th (Irish) Bn, the King's (Liverpool) (joined January 1918)

2/5th Bn, the King's (Liverpool) (joined February 1915, disbanded February 1918)

2/6th Bn, the King's (Liverpool) (joined February 1915)

2/7th Bn, the King's (Liverpool) (joined February 1915)

2/8th (Irish) Bn, the King's (Liverpool) (joined February 1915, absorbed by 1/8th Bn, January 1918)

171st Brigade Machine Gun Company (joined February 1917, moved into 57 MG Bn 1 March 1918)

171st Trench Mortar Battery (joined February 1917)

172nd (2nd South Lancashire) Brigade

1/9th Bn, the King's (Liverpool) (joined January 1918)

2/9th Bn, the King's (Liverpool) (joined February 1915, aborbed by 1/9th Bn, January 1918)

2/10th (Scottish) Bn, the King's (Liverpool) (joined February 1915, left April 1918)

2/4th Bn, the South Lancashire (joined February 1915)

2/5th Bn, the South Lancashire (joined February 1915, disbanded February 1918)

1st Bn, the Royal Munster Fusiliers (joined April 1918)

172nd Brigade Machine Gun Company (joined February 1917, moved into 57 MG Bn 1 March 1918)

172nd Trench Mortar Battery (joined February 1917)

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Divisional Troops

2/5th Bn, the Loyal North Lancs (joined as Pioneers February 1918)

173rd Machine Gun Company (joined 31 March 1917, joined Divisional MG Battalion 1 March1918)

No 57 Machine Gun Battalion (created 1 March1918)

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Divisional Mounted Troops

2nd County of London Yeomanry (left August 1915)

A Squadron, 2/1st Bedfordshire Yeomanry (did not proceed to France)

1st Kent Cyclist Bn (left 2 December 1915)

57th Divisional Cyclist Company (did not proceed to France)

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Divisional Artillery

CCLXXXV (2/I West Lancashire) Brigade, RFA

CCLXXXVI (2/II West Lancashire) Brigade, RFA

CCLXXXVII (2/III West Lancashire) Brigade, RFA (broken up by 20 February 1917)

2/IV West Lancashire (H) Brigade, RFA (broken up in July1916)

1st Lancashire Heavy Battery, RGA (a Battery of 4 4.7-inch guns which left the Division to move to France in December 1915)

2/1st Lancashire Heavy Battery, RGA (a Battery of 4 4.7-inch guns which joined 26 November 1915 but did not proceed to France with the Division. It eventually moved independently and joined II ANZAC in July 1916.)

57th Divisional Ammunition Column

W.57 Heavy Trench Mortar Battery RFA (joined 1 March 1917, left to join XV Corps 17 February 1918)

X.57, Y.57 and Z.57 Medium Mortar Batteries RFA (joined 1 March 1917; in February 1918, Z broken up and batteries reorganised to have 6 x 6-inch weapons each)

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Engineer Units, RE

421st Field Coy (joined Dec 1915, formerly named 1/3rd (West Lancs) Field Coy)

422nd Field Coy (left Dec 1915, formerly named 2/1st (West Lancs) Field Coy)

423rd Field Coy (left Dec 1915, formerly named 2/2nd (West Lancs) Field Coy)

502nd Field Coy (joined Dec 1915, formerly named 1/3rd (Wessex) Field Coy)

505th Field Coy (joined Feb 1916, formerly named 2/3rd (Wessex) Field Coy)

57th Divisional Signal Company (renamed from 2/1st West Lancashire Divisional Signal Company, which was formed in September 1915). Original company left the Division 8 December 1915.

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Field Ambulances, RAMC

2/1st West Lancashire (left 7 Dec 1915)

1/2nd West Lancashire (left 22 Oct 1915)

1/3rd West Lancashire (left 7 Dec 1915)

2/2nd Wessex (joined 4 Dec 1915)

2/3rd Wessex (joined 5 Dec 1915)

3/2nd West Lancashire (joined 4 Dec 1915)

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57th Divisional Train ASC (The original Divisional Train of the First Line 55th Division, formed in September 1915 and composed of 505, 506, 507 and 508 Companies ASC. It remained at home when the units of the 55th Division moved to France, and was transferred to the 57th (2nd West Lancashire) Division.

248th Divisional Employment Company (formed by 16 June 1917, adopting its number in August)

57th Mobile Veterinary Section (joined by September 1916)

57th Sanitary Section ( left for Second Army 15 April 1917)