At the end of book #1, it states that the journal continues on to journal #2 yet when Lil'Gideon had journal #2 he didn't know there was an existence of journal #3.
Gravity Falls: Journal 3 (hardcover) By Alex Hirsch, Rob Renzetti, Andy Gonsalves, Stephanie Ramirez : Target
Journal 1 | Gravity Falls Wiki | Fandom
Gravity Falls Journal 1-2-3 Unofficial Big Size English - Etsy
Gravity Falls Journal: Gravity Falls Fan Made Prop Book Journal | Gravity Falls Journal 1 2 3 diary | Hardcover Notebook.: Press, Proop Kings: 9798481360034: Amazon.com: Books
Three Keys - Journal 1 Gravity Falls by KisaraAkiRyu on DeviantArt | Gravity falls journal, Gravity falls book, Gravity falls journal 1
Journal 1 Page by HiyaItsJake on DeviantArt
Journal 1 | Gravity Falls Wiki | Fandom
ArtStation - Journals #1 #2 and #3 (Gravity Falls)
Deepest Chant - Journal 1 Gravity Falls by KisaraAkiRyu on DeviantArt
Gravity Falls Journal 1-2 Unofficial 20x27 Cm English - Etsy
Journal 1- Gravity Falls" Hardcover Journal for Sale by wanderingent | Redbubble
Anyone interested in buying, Journal 1 and 2 are special made with all the pages they show in the series, Journal 3 is the special edition. : r/ gravityfalls
Gravity Falls Journal 3: Gravity Falls Prop Book Journal | Gravity Falls Journal 1 2 3 Fan Edition Diary | Back To School Notebook: Luz Kiddies Press: 9798486470783: Amazon.com: Books
Gravity Falls Journal 4: Gravity Falls Fan Made Prop Book Journal | Gravity Falls Journal 1 2 3 diary | Hardcover Edition.: Press, Proop Kings: 9798483913399: Amazon.com: Books