The Rosby road is a road in the Crownlands running from the Iron Gate at King's Landing through Rosby to Duskendale. After Rosby, the road to Duskendale passes apple orchards and fields of barley and becomes rutted.
A Clash of Kings
As Hand of the King, Tyrion Lannister has Ser Jacelyn Bywater and the gold cloaks lay a trap on the Rosby road for Ser Boros Blount of the Kingsguard who is leading an escort for Prince Tommen Baratheon and Lord Gyles Rosby. Ser Jacelyn takes Prince Tommen without a fight and into Tyrion's protection at Rosby, rather than Queen Regent Cersei Lannister's, and replaces the Rosby garrison with fifty of his best men.
A Feast for Crows