Consider also "acquiescence":
Quote Quoting Merriman v. Cokeley, 168 Wn.2d 627, 230 P.3d 162 (2010).
A party claiming title to land by mutual recognition and acquiescence must prove (1) that the boundary line between two properties was "certain, well defined, and in some fashion physically designated upon the ground, e.g., by monuments, roadways, fence lines, etc."; (2) that the adjoining landowners, in the absence of an express boundary line agreement, manifested in good faith a mutual recognition of the designated boundary line as the true line; and (3) that mutual recognition of the boundary line continued for the period of time necessary to establish adverse possession (10 years). Lamm v. McTighe, 72 Wash.2d 587, 593, 434 P.2d 565 (1967). These elements must be proved by clear, cogent, and convincing evidence. Lilly v. Lynch, 88 Wash.App. 306, 316-17, 945 P.2d 727 (1997). To meet this standard of proof, the evidence must show the ultimate facts to be highly probable. Douglas Nw., Inc. v. Bill O'Brien & Sons Constr., Inc., 64 Wash. App. 661, 678, 828 P.2d 565 (1992).
Adverse possession is more difficult to prove,
Quote Quoting ITT Rayonier, Inc. v. Bell, 112 Wash.2d 754, 774 P.2d 6 (1989)
In order to establish a claim of adverse possession, there must be possession that is: (1) open and notorious, (2) actual and uninterrupted, (3) exclusive, and (4) hostile. Chaplin v. Sanders, 100 Wn.2d 853, 857, 676 P.2d 431 (1984). Possession of the property with each of the necessary concurrent elements must exist for the statutorily prescribed period of 10 years. RCW 4.16.020. As the presumption of possession is in the holder of legal title, Peeples v. Port of Bellingham, 93 Wn.2d 766, 773, 613 P.2d 1128 (1980), overruled on other grounds in Chaplin v. Sanders, supra, the party claiming to have adversely possessed the property has the burden of establishing the existence of each element. Skansi v. Novak, 84 Wash. 39, 44, 146 P. 160 (1915), overruled on other grounds in Chaplin v. Sanders, supra.
Neither cause of action is automatic. You have to go to court and prove that all elements have been satisfied before a court will grant you rights to a neighbor's land.