| Static Image Name: | Woolsthorpe manor.jpg |
| Static Image Caption: | Birthplace of Sir Isaac Newton |
| Country: | England |
| Official Name: | Woolsthorpe-by-Colsterworth |
| Coordinates: | 52.8099°N -0.6288°W |
| Civil Parish: | Colsterworth |
| Shire District: | South Kesteven |
| Shire County: | Lincolnshire |
| Region: | East Midlands |
| Constituency Westminster: | Grantham and Stamford |
| Post Town: | Grantham |
| Postcode District: | NG33 |
| Postcode Area: | NG |
| Os Grid Reference: | SK925244 |
| London Distance Mi: | 95 |
| London Direction: | SSE |
Woolsthorpe-by-Colsterworth (to distinguish it from Woolsthorpe-by-Belvoir in the same county) is a hamlet in the South Kesteven district of Lincolnshire, England. It is best known as the birthplace of Sir Isaac Newton.
Woolsthorpe-by-Colsterworth is 1miles northwest of the village of Colsterworth on the A1 road. Woolsthorpe is three miles from the county boundary with Leicestershire and four miles from the county boundary with Rutland.
Woolsthorpe lies in rural surroundings. It sits on Lower Lincolnshire Limestone, below which are the Lower Estuarine Series and the Northampton sand of the Inferior Oolite Series of the Jurassic period. The Northampton Sand here is cemented by iron and in the 20th century the hamlet was almost surrounded by strip mining for iron ore. In 1973 the local quarries closed due to competition from imported iron ore. The same year the Great Northern Railway's High Dyke branch line closed it was opened in 1916 to carry iron ore, and lay to the north of the village. There was an unsuccessful attempt to preserve the line.
Woolsthorpe Manor, Newton's birthplace, is a typical 17th-century yeoman farmer's limestone house, with later farmyard buildings. It is owned by the National Trust and is open to the public.