Utah Code § 10-2-814

(1) As used in this section: (a) "Most populous bordering municipality" means the municipality with the highest population of any municipality that shares a common border with an unincorporated island. (b) "Unincorporated island" means: (i) within a county of the first class, an area that is: (A) not within a municipality; and (B) completely surrounded by land that is within one or more municipalities within the county of the first class; or (ii) within a county of the second class, an area: (A) that is 55 acres or smaller; (B) that is not within a municipality; (C) that is completely surrounded by land that is within one municipality within the county of the second class; and (D) (I) to which the municipality that completely surrounds the area provides sanitary sewer service or culinary water service; (II) that does not contain any public infrastructure; or (III) that contains public infrastructure that currently meets the municipal code and standards of the municipality that completely surrounds the area. (2) Notwithstanding any other provision of this part, on July 1, 2027, an unincorporated island within a county of the first class is automatically annexed to: (a) the most populous bordering municipality, except as provided in Subsection (2)(b); or (b) a municipality other than the most populous bordering municipality if: (i) the other municipality shares a common border with the unincorporated island; and (ii) the other municipality and the most populous bordering municipality each adopt a resolution agreeing that the unincorporated island should be annexed to the other municipality. (3) Notwithstanding any other provision of this part, and except as provided in Subsection (6) or (7), on July 1, 2027, an unincorporated island within a county of the second class is automatically annexed to the municipality that completely surrounds the unincorporated island. (4) (a) No later than May 1, 2027, a county of the second class in which an unincorporated island will be automatically annexed shall: (i) mail written notice to each owner of real property located within the unincorporated island that includes: (A) a description and map of the unincorporated island; (B) the effective date of the automatic annexation; and (C) information about the municipality into which the unincorporated island will be annexed including: (I) a summary of services the municipality provides; and (II) the municipality's contact information; and (ii) publish notice of the automatic annexation on the Utah Public Notice Website. (b) A county required to provide the notice described in Subsection (4)(a) shall consult with the applicable municipality when preparing the notice. (c) The notice described in Subsection (4)(a) is in addition to any boundary certification or recording requirements under this chapter. (5) The effective date of an annexation under Subsection (2) or (3) is governed by Section 10-2-813. (6) A legislative body of a county of the second class with a population of less than 600,000 may exempt an unincorporated island or a portion of an unincorporated island from the requirements of this section by adopting a resolution on or before May 1, 2027, that includes a description or map of each exempted unincorporated island or portion of an unincorporated island. (7) In a county of the second class with a population of 600,000 or more, a legislative body of a municipality may exempt an unincorporated island or a portion of an unincorporated island from the requirements of this section by adopting a resolution on or before May 1, 2027, that includes a description or map of each exempted unincorporated island or portion of an unincorporated island.