Sarah Ann Rigelsford was born in London, England, probably in 1821 or 1822. Her mother's name is unknown; her father was John Rigelsford, a labourer. She was clever at needlework and as a young woman she set up her own dressmaking business. On 15 April 1844 in the parish of St Mary Lambeth, London, she married Isaac Cripps, a member of the London Metropolitan Police Force.
In 1849 Isaac resigned as a policeman and signed a contract with Charles Enderby's whaling company, which had plans to establish a whaling base and settlement in the Auckland Islands. Reluctantly in 1849 Sarah sailed with Isaac and their three children in the Fancy. The settlers endured two years of hardship on the islands before the enterprise was abandoned. The Cripps family departed for Wellington in the brig Kitty in 1852. Sarah's fourth child had been born at Port Ross on the Auckland Islands the previous year.
In Wellington the Cripps family lived in a shack near Island Bay for two years, and while they were there the fifth child was born. Isaac worked as a labourer in Wellington until 1854 when the family sailed for Wairarapa, landing at Castlepoint and travelling on to the Mataikona property of John Valentine Smith, where Isaac worked as a farm labourer and where the sixth child was born. Two years later they moved inland and lived in a shanty on the banks of the Whareama River while Isaac worked as a shepherd for runholder Henry Buxton. In 1857 twins were born and Isaac bought 40 acres of land for £20, building a house named Sevenoaks after his home in Kent.
Whareama was on the main route between Wellington and Hawke's Bay, and Isaac and Sarah Cripps decided to operate Sevenoaks as an accommodation house. Soon Sarah became known as an excellent cook and hostess and she and her husband built up an enduring reputation for hospitality. To meet the needs of settlers and travellers Sarah opened a shop and post office. Although Isaac was appointed postmaster in 1863, Sarah conducted the day-to-day affairs of the post office and handled mail to and from Whareama on the Masterton–Castlepoint mail service.
As accommodation-house keeper, shopkeeper and postmistress Sarah Cripps was a respected figure in Wairarapa in the 1860s and 1870s, but perhaps her greatest importance was as a midwife. The nearest doctor was 20 miles away in Masterton: when babies were due to be born the call would go out for Granny Cripps. She was never known to refuse a call, even if it was necessary to make a long or arduous journey. However, she hated riding, and always sat side saddle while someone else led her horse.
After Sevenoaks was built, Sarah bore two more children; besides nursing, feeding guests and running the post office and shop, she had the responsibility of raising and educating her own family of 10 children. Through all this work she made an essential contribution to the stability of an isolated community. It is not surprising that by the time of her death in Wellington on 8 June 1892 she was called 'the best loved woman from Wellington to Ahuriri'.