<P> Arngrim left the series at the end of the seventh season . Nellie 's resulting departure was explained by having her move with Percival and their twins to New York to run the family business when Percy 's father falls ill ; the move is made permanent when Percival 's father dies . After Nellie 's departure became permanent , the Olesons adopted a daughter named Nancy ( played by Allison Balson ) , who bore a striking resemblance to Nellie , although she had a nastier and meaner disposition than Nellie . Nellie -- who retained her pleasant personality seen in her later years -- returned in the ninth season and met Nancy , who briefly ran away from home when she ( mistakenly ) believed that her adoptive parents loved Nellie more than her . When Nellie first meets Nancy and see how she acts , she asks her parents in shock : `` I know I was temperamental at her age , but I was n't THAT bad ... Was I ? '' They all start to laugh , then they realize she was as bad . </P>
<P> Arngrim left the series at the end of the seventh season . Nellie 's resulting departure was explained by having her move with Percival and their twins to New York to run the family business when Percy 's father falls ill ; the move is made permanent when Percival 's father dies . After Nellie 's departure became permanent , the Olesons adopted a daughter named Nancy ( played by Allison Balson ) , who bore a striking resemblance to Nellie , although she had a nastier and meaner disposition than Nellie . Nellie -- who retained her pleasant personality seen in her later years -- returned in the ninth season and met Nancy , who briefly ran away from home when she ( mistakenly ) believed that her adoptive parents loved Nellie more than her . When Nellie first meets Nancy and see how she acts , she asks her parents in shock : `` I know I was temperamental at her age , but I was n't THAT bad ... Was I ? '' They all start to laugh , then they realize she was as bad . </P>
who is nancy oleson on little house on the prairie
who is nancy oleson on little house on the prairie
Allison Balson
Allison Balson