Published
The mechanism that needs 320 acres is rare. This one needs twenty.
Twenty acres is the number that should interest a cabin owner
The county's headline mechanism for reshaping rural ground needs 320 acres, which puts it out of reach almost everywhere. The Rural Mixed Use Overlay needs twenty. That is an ordinary holding in this county, and it is the reason this is the mechanism you are far more likely to meet.
“The purpose of the Rural Mixed Use (RMU) overlay district is to allow flexibility in site design and dimensional standards to develop residential, commercial and/or industrial uses not allowed individually within specific zoning districts… The minimum area for a Rural Mixed Use Overlay shall be twenty (20) acres.”
— Fremont County Development Code, 2011 Edition (Ordinance 2011-04), sections 4.18.010 and 4.18.020. Consolidated through Ordinance 2026-03. Retrieved 1 September 2026
Read that purpose clause slowly, because it is doing something unusual. It permits residential, commercial and industrial uses that are not allowed individually in the underlying zone. An overlay does not replace the base district; it sits on top of it and changes what the base district would otherwise permit.
The three triggers — and any one of them is enough
Section 4.18.020(b) says the overlay is required for any development or subdivision proposal involving one or more of the following. That word “required” matters: this is not only an opportunity a developer may take, it is a route they must use if their proposal has any of these features.
| Trigger | What it covers |
|---|---|
| Mixed uses | A mix of uses that are not allowed as principal permitted or conditional uses in the same base district |
| Clustering away from hazards | Clustering residential units away from physical constraints or hazardous areas — flood hazards, unstable geologic conditions, soil conditions, topography, identified high ground water areas, and other characteristics that could threaten public health or safety |
| Dimensional deviation | Deviation of dimensional standards to achieve dedicated open space and provide amenities not found in traditional subdivisions |
The second trigger is the one that fires most often on Island Park ground, and it is worth understanding as information rather than as a threat. High ground water, difficult soils and awkward topography are ordinary conditions here. When a developer clusters houses onto the good ground and leaves the wet or unstable part alone, the code makes them use this overlay to do it.
Which means, from a neighbour's point of view: an RMU application is often evidence that part of the ground has a problem. That is genuinely useful intelligence about a parcel next to yours — and about your own, if the same conditions run across the boundary.
What the county is trying to get out of it
Section 4.18.030 lists what a successful overlay should produce:
- A more efficient, aesthetic and desirable use of open space and recreational amenities.
- A density compatible with abutting development — the clause a neighbour would cite.
- An integrated development served by adequate public services and facilities.
- Protection of existing natural, scenic, and historic resources.
- Protection of existing neighbourhoods through buffering techniques including screen planting, open space, and landscaping.
“Density compatible with abutting development” is the standard that most directly protects an existing cabin owner, and it is written into the objectives rather than left to discretion.
It is a rezoning, which is the important part
Like its larger sibling, an RMU is not an administrative approval. The applicant must comply with the regulations for a Zoning Ordinance Map Amendment under Chapter 3 and concurrently obtain the subdivision approval that goes with it.
A map amendment carries public notice and a hearing. For a landowner nearby, that is the whole practical answer to “would I find out?” — yes, and there is a defined moment to say something. The objectives above are the language to use when saying it: compatible density, adequate services, buffering of existing neighbourhoods.
The two mechanisms side by side
| Rural Mixed Use Overlay | Rural Village District | |
|---|---|---|
| Minimum area | 20 acres | 320 acres |
| What it does | Sits on top of the base zone and permits uses or dimensions it would not | Creates a new community with its own identity |
| Distance rule | None stated | More than five miles from a city, area of impact, or previous village |
| Approval | Zoning Ordinance Map Amendment | Map amendment plus a Class II Large-Scale Subdivision Permit |
| Likelihood near an ordinary lot | Realistic | Rare |
The 320-acre mechanism and its five-mile rule are set out here.
What to do with this when buying
- Look at the neighbouring holdings, not just the neighbouring lot. Twenty acres in one ownership is enough. The parcel viewer shows you who owns what on every side.
- Treat a nearby RMU application as a soil report you did not pay for. If someone is clustering away from high ground water or unstable ground, ask whether those conditions cross onto the parcel you are buying.
- Know your own base zone first, because an overlay is defined by what it changes — and the map only gives you a letter.
- Read the open-space obligation separately. Both mechanisms carry one, and the percentages are set out in the rural open space and density rules rather than here.
And the standing rule for reading this code at all still applies: what is not listed is prohibited. An overlay is one of the few written routes to a use the base district does not name, which is exactly why the code makes it a rezoning rather than a permit.
Common questions
What is a Rural Mixed Use Overlay in Fremont County?
An overlay district under section 4.18 that allows flexibility in site design and dimensional standards to develop residential, commercial and industrial uses that are not allowed individually within a specific zoning district. It sits on top of the base zone rather than replacing it.
How much land does a Rural Mixed Use Overlay need?
A minimum of twenty acres. That is an ordinary holding in this county, which is why this mechanism is far more likely to appear near a cabin lot than the 320-acre Rural Village District.
When is the overlay required rather than optional?
It is required for any development or subdivision proposal involving a mix of uses not allowed in the same base district, clustering of residential units away from hazards, or deviation of dimensional standards to achieve dedicated open space and amenities.
What hazards trigger the clustering provision?
The code names flood hazards, unstable geologic conditions, soil conditions, topography and identified high ground water areas, plus other characteristics that could threaten public health or safety.
Why does a neighbouring overlay application tell me something about my own land?
Because the clustering trigger fires when part of a parcel has a problem — high ground water, difficult soils, awkward topography. If a developer is clustering away from those conditions next door, it is worth asking whether they cross the boundary onto your ground.
Does an overlay require a rezoning?
Yes. The applicant must comply with the regulations for a Zoning Ordinance Map Amendment under Chapter 3 and concurrently obtain the subdivision approval that goes with it, so it carries public notice and a hearing.
What protects an existing cabin owner nearby?
The code's stated objectives include a density compatible with abutting development, adequate public services and facilities, and protection of existing neighbourhoods through buffering such as screen planting, open space and landscaping.
How is the overlay different from the Rural Village District?
Scale and purpose. The overlay needs 20 acres and modifies what the base zone permits; the Rural Village District needs 320 acres, must sit more than five miles from any city or previously approved village, and creates a new community with its own identity.
Does the overlay change my own lot?
Only if it is applied to your ground. An overlay is mapped, so it affects the parcels inside it. Its relevance to a neighbour is what it permits nearby and what conditions the approval attaches.
Where do I find the open space requirement for these districts?
It is set out with the county's other rural open space and density rules rather than in the overlay section itself, and the percentages differ between the overlay and the Rural Village District.