John Ainsworth Horrocks (22 March 1818 – 23 September 1846) was an English pastoralist and explorer who was one of the first European settlers in the Clare Valley of South Australia where, in 1840, he established the village of Penwortham.

Impatient to settle on their own land, the brothers set up camp on 16 January 1840 at present Penwortham, a village which they founded and named.

[2] On 29 July 1846 he commenced an exploratory expedition into the far north-west of South Australia, aiming for distant hills near Lake Torrens, hoping to find good agricultural land.

The several hired men included Bernard Kilcoy as cook and driver, and goatherd Jimmy Moorhouse, a young Aboriginal employee at his Penwortham station.

[4][5] The expedition was abandoned and the party returned to Horrocks's home at Penwortham, where he died of his wounds on 23 September.