High Hazels Park is a 20-hectare park in Darnall, known for its historical ties to the coal and steel industries. The park features High Hazels House, built in 1850 by William Jeffcock, Sheffield's first mayor.

William Jeffcock, born in 1800 in Handsworth, South Yorkshire, was the son of a colliery owner. He married Judith Stobart in 1827, and they had four children. Jeffcock played a key role in Sheffield's incorporation, becoming its first Mayor in 1843. He served as a Justice of the Peace and Major in the Yeomanry Cavalry. In 1850, he built High Hazels House on his estate, now a golf clubhouse. Jeffcock died in 1871 and was buried in Sheffield.

The Sheffield City Council purchased the estate in 1894, converting it into a public park by 1895. High Hazels House, originally a lavish residence, became a museum in 1901, attracting thousands of visitors, and later served as a base for the Home Guard during WWII. The museum closed post-war, and the house now functions as the clubhouse for Tinsley Park golf course. The Formal Garden, redesigned with community input, was opened in 2005.