170th (2/1st North Lancashire) Brigade was a 2nd-Line infantry formation of the British Territorial Force raised during the First World War that served on the Western Front.

In July 1916, 57th Division was transferred to the Emergency Reserves in the Aldershot area where it continued training.

[6] On 5 January 1917 the division was ready for overseas service, and between 7 and 22 February its units and formations crossed to France and disembarked at Le Havre.

On 25 February it took over a section of the Front Line under the command of II ANZAC Corps.

The last cadres of 57th Division left France in July 1919, completing the disbandment of 170 Bde.