| Unit Name: | 1st Division 1.ª División |
| Dates: | 1936–1939 |
| Country: | Spain |
| Branch: | Spanish Republican Army |
| Type: | Infantry division |
| Role: | Home Defence |
| Command Structure: | 1st Army Corps (1936–1939) |
| Garrison: | Lozoyuela |
| Battles: | Spanish Civil War |
| Notable Commanders: | Enrique Jurado Barrio |
The 1st Division (Spanish; Castilian: 1.ª División) was a division of the Spanish Republican Army in the Spanish Civil War.
This unit was deployed in a relatively inactive section of the front located in the mountainous area north of Madrid.
The First Division was established on 31 December 1936 with the militia forces that had been operating in the Somosierra sector and which had been led by Lt. Colonel Enrique Jurado Barrio. The headquarters of the division was in Loyozuela.
This unit was garrisoned at the secondary sector of El Escorial and did not take part in any important military operation. The commander who replaced Enrique Jurado, Lt. Colonel Fernando Cueto Herrero, was discovered when he was trying to join the enemy forces and was summarily dismissed and shot for treason on 18 September 1937. Except for a few sporadic skirmishes the unit rarely saw combat action and was mainly engaged in fortification work. The First Division was disbanded at the end of the war in late March 1939.
| Date | Army Corps | Mixed Brigades | Battlefront | |
|---|---|---|---|---|
| December 1936 | 1st Army Corps | |||
| December 1937 | 1st Army Corps | Center | ||
| April 1937 | Center | |||
| November 1938 | Center |