Subject to subsection (b) of this section, two or more abutting municipalities located in the same county may merge to form one municipality. The governing body of the county must approve any merger under this subtitle.

To initiate a merger, the legislative body of each municipality shall adopt a proposal of unification. Each municipality shall adopt the proposal of unification: in substantially identical form; and in the manner that the municipality adopts ordinary legislation. The proposal of unification shall include a detailed description of the boundaries of the proposed municipality that: is comprised of a survey of courses and distances; and may refer to general landmarks and place names.

After both municipalities adopt the proposal of unification, the municipalities shall prepare a unified charter. Each municipality shall appoint three, four, or five representatives to serve on a charter commission. Each municipality shall appoint the same number of representatives. The representatives shall meet as a charter commission. Within 6 months after the municipalities adopt the proposal of unification, the commission shall draft a proposed unified charter. The charter commission shall elect officers from among the representatives. As the representatives consider necessary, the charter commission may adopt rules to govern meetings and expedite the drafting of the unified charter.

The unified charter is a legal document separate from any other legal instrument. The unified charter shall provide that the unified municipality receive the assets and liabilities of the merging municipalities.

The charter commission shall submit a proposed unified charter to the legislative body of each municipality. The legislative body shall include the proposed charter in a resolution that is considered in accordance with the procedural requirements provided for charter amendments in §§ 4–303(a) and 4–304 of this title. For purposes of § 4–303(a) of this title, the resolution is considered to embrace only one subject. Each legislative body may: adopt or reject the resolution; or amend the resolution, if the legislative bodies of the other municipalities concur.

If a referendum is required under § 4–304 of this title, the referendum shall occur on the same day in each municipality. Each municipality shall administer and pay for the referendum in proportion to its respective population. In a referendum, the unified charter is adopted if a majority of votes cast in each municipality is in favor of adoption.

If a majority of the voters casting votes in any municipality at a referendum do not vote to adopt the unified charter, the proposed merger is not approved. If the unified charter is adopted, by referendum or by the legislative bodies when a referendum is not required, the adoption is final.

A merging municipality shall transfer its assets and liabilities to the unified municipality. The merging municipality shall transfer the assets and liabilities by legal instruments separate from the unified charter and resolution. The invalidity of a legal instrument that transfers or disposes of any property of a merging municipality does not affect the validity of the unified charter. Within 60 days after the unified charter is adopted, the legislative bodies of the merging municipalities jointly shall send the information concerning the charter to the Department of Legislative Services as provided in § 4–109 of this title. The exact text of the unified charter adopted under this subtitle, including any amendments, shall be included in any edition or codification of the charter.

Unless the zoning classification is amended under the procedures required by the county, for 5 years after the effective date of the unified charter, the land of a merging municipality that does not have planning and zoning powers may not be placed in a zoning classification that allows a land use substantially different from the use allowed by the master plan or plan of the county or agency that has planning and zoning jurisdiction over the land before the merger. This subtitle does not grant planning and zoning powers to a unified municipality if none of the merging municipalities has planning and zoning powers.