Elizabeth Lewis was born in Machynlleth, Montgomery (about 5 miles from Corris and 10 miles away from Talyllyn) in 1798. The 1851 census gives her age as 53, it was taken on 31st March 1851, so implying a birth between 1 Apr 1797 and 30 Mar 1798
IGI gives birth: 09 Jan 1798 Christening: 12 Jan 1798 at Llanwrin, Montgomery, daughter of Humphrey Lewis (or Lewis Humphrey in Welsh patronomic). Mother: Elizabeth
Llanwrin is near Machynlleth, and the date of birth does fit exactly with the census information.
She married Rees Thomas They had seven children, six daughters and one son. The marriage must have been around 1824 or 1825, and could have been in England, as their first child was born in Stockport in1824 and was probably illegitimate.
1824 The first child was their daughter Sarah who was born in Stockport in 1824 and baptised at the Independent Church in Churchgate, Stockport, on Christmas Day, 25th December 1824. It is not known why she was living in Stockport in 1824. Sarah ws almost certainly illegitimate, but one cannot tell if Rees Thomas was the father. I assume that she married Rees sometime after this and before the next child was born in Talyllyn in March 1826.
The full details of her life after marriage and the births of their children can be found under her husband Rees Thomas.
The family first lived at Maesygorwyr, which lies behind Tynyberth towards Llyn Eiddaw. In 1835 the Thomas family left Maesygorwyr and lived in Tan'r Ewan (Under the Yew), later known as Tyriwen, one of two houses that backed onto the churchyard at Talyllyn. There is now no trace of the pair of houses that were known as Tan'r Ewan. They are there in 1841 and 1851 census
1855. Following her uncle's David Thomas death aged 76, Rees Thomas and Elizabeth moved from Tan'r Ewan in Talyllyn to Fron Yw in Dolgellau
1857 Elizabeth Lewis died 20 Dec 1857 age 60 at Fron Yw. She was buried at Talyllyn on the Christmas Eve.
Elizabeth Thomas (nee Lewis) grave at Tal-y-llyn
Her husband Rees Thomas lived on till 1870 in Dolgellau at Fron Yw. Rees Thomas lived there with two of his unmarried daughters Catherine and Mary. In censuses, Catherine is described as a housekeeper and Mary variously as housekeeper and cook. So it would appear that Rees Thomas was well looked after in the evening of his life.