Castleshaw

{{Use dmy dates|date=February 2015}}

{{Use British English|date=February 2015}}

{{Infobox UK place

| country = England

| coordinates = {{coord|53.583|-1.999|display=inline,title}}

| label_position = left

| official_name = Castleshaw

| population =

| civil_parish = Saddleworth

| metropolitan_borough = Oldham

| metropolitan_county = Greater Manchester

| region = North West England

| constituency_westminster = Oldham East and Saddleworth

| post_town = OLDHAM

| postcode_district = OL3

| postcode_area = OL

| dial_code = 01457

| os_grid_reference = SE000096

| static_image = Castleshaw, Bleak Hey Nook Lane (geograph 3042225).jpg

| static_image_caption = Bleak Hey Nook Lane, Castleshaw

| london_distance =

}}

Castleshaw is a hamlet in the Saddleworth parish of the Metropolitan Borough of Oldham in Greater Manchester, England.{{cite map|title=Ordnance Survey: Landranger map sheet 109 Manchester (Bolton & Warrington)|ISBN= 9780319231555 |publisher=Ordnance Survey|date=2014}} It lies amid the Pennines, {{Convert|2.4|mi|km|1}} north of Uppermill, {{Convert|3|mi|km|1}} west-southwest of Marsden, and {{Convert|5.3|mi|km|1}} east-northeast of Oldham.

Historically a part of the West Riding of Yorkshire, Castleshaw is most notable for the Castleshaw Roman fort, the remains of an ancient castrum. There are two reservoirs, Castleshaw upper reservoir and Castleshaw lower reservoir. In 2016, United Utilities reinforced the walls on the lower reservoir but had to drop water levels by 1m.