Sir John Ross is a minor character in AMC's The Terror.
In The Show[]
Ross first appears in episode 3 having a discussion with Sir John Franklin about the latter's rescue plans should something go wrong. He then appears in the next episode when Lady Jane Franklin and Sophia Cracroft implore the government to start sending search parties for her missing husband. He agrees with Mrs. Franklin's assessment that Sir John is most likely stuck in the ice and that it's probably better expend pounds now rather than lives later.
He is mentioned by Thomas Blanky in episode 5 after Captain Francis Crozier is restrained for attacking Captain James Fitzjames. Blanky warns Crozier that if he's not careful what happened to Sir John Ross at Fury Beach will happen to him. In the next episode Fitzjames asks Blanky what he meant regarding Sir John and Fury Beach. Blanky explains it to him in more detail regarding a previous expedition Blanky was a part of with Ross as it's captain and how Ross's lack of sympathy and care for many of his men made Blanky want to murder him. Blanky advises Fitzjames that if they are going to abandon the ships and walk overland to safety, it's best to give the men something in return in order to raise morale and prevent feelings of resentment.
In The Book[]
Ross appears in a flashback/fever dream of Sir John Franklin in chapter 2. While Crozier was going through his alcohol withdrawal he was a premonition of Ross on the schooner "Felix" in 1850 living up to the vow he made that he would search for Franklin if they hadn't heard from him by then.