Adverse Possession and Municipal Parkland: The Implications of Kosicki v Toronto (City), 2025 SCC 28

This article was originally published in Law360 Canada.

In a closely divided five‑to‑four ruling in Kosicki v Toronto (City), 2025 SCC 28, the Supreme Court of Canada confirmed that municipalities and other public bodies in Ontario are not immune to adverse possession claims, unless the land in question is explicitly protected by legislation.

This breakthrough decision carries significant implications for landowners and public authorities across Ontario, particularly municipal planners and legal departments who must now reassess their land management practices to mitigate exposure and preserve public assets.

Facts

Pawel Kosicki and Megan Munro purchased a residential property in Toronto in 2017, only to later discover that a portion of their backyard was municipally owned and designated as parkland. The land had been expropriated by the Metropolitan Toronto and Region Conservation Authority in 1958 and conveyed to the City in 1971. That portion of the backyard had been enclosed by a fence since at least 1971, preventing public access to the disputed land.

Despite the exclusively private use of the land for decades, the City refused to sell the disputed land to Pawel and Megan, citing its green space policy.

In 2022, Mr. Kosicki and Ms. Munro brought an application under Ontario’s Real Property Limitations Act (RPLA) for adverse possession.

What is Adverse Possession?

Adverse possession, often referred to as “squatters’ rights,” allows a person to acquire legal title to land if they have occupied it for a period of 10 years. For an adverse possession claim to succeed, the trespasser must establish:

1)    Actual possession of the land for the required period;

2)    An intention to exclude the true owner; and

3)    Effective exclusion of the true owner.

Actual possession is established when the occupation of land is:

·         Open and notorious – the use of the land is widely recognized and apparent;

·         Adverse – the possession is without the permission of the true owner and inconsistent with their rights;

·         Exclusive – the claimant exercises control over the land to the exclusion of the true owner and others;

·         Peaceful – the possession is maintained without force, threats, or ongoing disputes; and

·         Actual and continuous – the claimant physically uses the land in a manner consistent with its nature and does so without significant interruption for the statutory period.

Provided these elements are met, the RPLA extinguishes the original owner’s title after the 10‑year limitation period. However, certain public lands are exempt from adverse possession claims under section 16 of the RPLA. This includes waste or vacant land of the Crown, road allowances, and public highways. Importantly, this exemption does not apply to municipal parkland.

Lower Court Decisions

Ontario Superior Court of Justice[1]

The application judge acknowledged that the homeowners met the traditional test for adverse possession. She then applied a “public benefit test” which turned on whether the land had ever actually been used by the public.

The application judge determined that the test was not met; the City could not defeat the possessory claim because it was unable to demonstrate the disputed land had ever been used by the public before the fence’s erection. Although the “public benefit” test was not met, the application judge dismissed the claim on public policy grounds. The application judge found that allowing private ownership of public parkland would set a dangerous precedent, as it would require public entities to employ an unreasonable level of resources to defend the public interest in lands against encroaching private owners.

Court of Appeal for Ontario[2]

The homeowners appealed to the Court of Appeal for Ontario. The majority reframed the “public benefit test,” removing the requirement of actual use and instead held that adverse possession claims against municipal land will fail if:

1. The land was acquired for or dedicated to public use, and

2. The municipality has not waived its rights to the land or acknowledged or acquiesced to its private use.

Similarly to the application judge, the majority concluded that the claim to the disputed land could not succeed. The majority found that the municipality had not waived its rights to the property or acquiesced to its private use.

The dissenting judge, however, argued that the RPLA governs the claim and that the common law test improperly amended the statute by providing immunity from adverse possession for municipal parkland.

The Supreme Court of Canada’s Decision

The homeowners, sought, and were granted leave appeal to the Supreme Court of Canada.

The Majority Reasons Allow the Appeal

In a narrow, five to four decision, the majority of the Court allowed the appeal, concluding that the RPLA governs the dispute and does not exempt municipal parkland. Writing for the majority, Justice O’Bonsawin emphasized that the appellants had satisfied all statutory requirements for adverse possession. As a result, the City’s title to the land had been extinguished roughly four decades prior under section 15 of the RPLA.

The majority rejected the lower courts’ reliance on a “public benefit test” as a basis to deny the claim. It held that recognizing a novel common law immunity for municipal parkland would be inconsistent with the statutory scheme and contrary to legislative intent. The RPLA contains a closed list of exemptions under section 16, which includes certain Crown lands, road allowances, and public highways, but does not include municipal parkland. The Court found that the legislature had deliberately chosen which categories of public land would be shielded from adverse possession and had preserved matured possessory claims even while abolishing new ones under the Land Titles Act (LTA). To create an additional exemption for municipal parkland through common law would undermine the RPLA’s purpose.

The Court reaffirmed that adverse possession remains a valid legal doctrine in Ontario, and that its application must be governed by statute, not by evolving common law tests that conflict with legislative intent. Ultimately, the Court declared the appellants to be the fee simple owners of the disputed land and ordered the land registry to reflect their title.

Four Dissenting Judges would have Dismissed the Appeal

Writing for the dissent, Justice Kasirer held that the RPLA does not reveal a clear legislative intent to oust the common law. In his view, the RPLA operates alongside common law principles, recognizing the unique nature of municipal public lands.

Central to the dissent’s reasoning was the “public benefit test,” which the Court of Appeal had reframed and applied in this case. Justice Kasirer stated this test did not create an immunity for municipal parkland. Instead, this test relies on a rebuttable presumption that land designated for public use, such as municipal parkland, is held in trust for the community and is therefore presumptively immune from adverse possession. To overcome this presumption, a claimant must provide clear and compelling evidence that the municipality either acknowledged or acquiesced to the private use of the land. Justice Kasirer found that the appellants failed to meet this high evidentiary bar. The presence of a fence, the payment of property taxes, and the lack of active monitoring by the City were insufficient to establish the kind of knowledge or consent required to defeat the public character of the land.

The dissent also highlighted the practical challenges municipalities face in monitoring vast portfolios of public land. With thousands of acres of parkland and hundreds of parks, it would be unreasonable to expect municipalities to patrol every boundary to prevent encroachments. They concluded that the public interest in preserving parkland for communal use outweighs the private interest in acquiring land through adverse possession.

Key Takeaways for Municipalities

The Court’s decision fundamentally alters the risk landscape for municipalities and other public entities in Ontario with significant land holdings. Below are some key implications to be considered by stakeholders across the province.

1. Increased Exposure to Claims

Municipalities now face heightened exposure to adverse possession claims over lands not expressly exempt under the RPLA. This includes parkland, greenbelts, and other public spaces historically assumed to be immune. Municipalities should anticipate potential claims, particularly where long-standing encroachments exist.

2. Need for Comprehensive Land Audits

Even if land is later registered under the LTA, providing protection against new adverse possession claims, matured possessory claims prior to registration remain valid. Accordingly, municipalities should conduct historical audits of land holdings, focusing on:

a)    Parcels acquired decades ago but never actively monitored;

b)    Lands with unclear or disputed boundaries; and

c)    Areas where fencing or exclusive private use has occurred.

3. Proactive Boundary Management

Municipalities should implement systematic inspection programs and maintain photographic and written records of property boundaries. Installing signage, repairing fences, and issuing encroachment notices can help demonstrate active assertion of ownership.

4.           Risk Management and Insurance

Municipal insurers should be consulted to assess coverage for adverse possession claims. Legal departments should develop protocols for responding to claims promptly to mitigate litigation costs.

5.           Public Communication

Municipalities should consider public education campaigns to clarify property boundaries and discourage unauthorized use of public lands, reducing the likelihood of future claims.

[1] Kosicki v. City of Toronto, 2022 ONSC 3473.

[2] Kosicki v. Toronto (City), 2023 ONCA 450.