Pull up a listing on Osona Lane and the address reads Mars, PA 16046. That single line tells you almost nothing about which government actually taxes the parcel, patrols the street, or has jurisdiction over the storm drain at the end of the cul-de-sac. Mars, PA 16046 is shared by two separate municipalities, Mars Borough and Adams Township, and this November both of them are asking voters the exact same question.
The gap that shows up between a "Mars" price and an "Adams Township" price on any home search isn't just about square footage or lot size. Part of it is a tax rate that Butler County voters will decide whether to erase entirely on November 3, 2026.
One Zip Code, Two Governments
Mars, PA 16046 covers Mars Borough, a small, traditional borough with its own council and mayor, and most of Adams Township, a 22.6-square-mile municipality run by a board of supervisors. Adams Township was created in 1854 as one of Butler County's two original townships, named for President John Quincy Adams, and has spent the last few decades converting farmland into subdivisions like Woodland Trace and Gabriel's Crest. Mars Borough kept its compact, walkable downtown and its own small-town government.
Because both places share a zip code, any "Mars, PA" median price you find is blending sales from two separate tax jurisdictions into one number. A buyer comparing a listing on Osona Lane to one a few streets over in the historic borough core could be comparing two different governments' worth of tax history without ever realizing it, since the shared zip code doesn't distinguish between them.
| Mars Borough | Adams Township | |
|---|---|---|
| Government structure | Council and mayor | Board of supervisors |
| Current municipal tax rate | Higher than Adams Township's, according to officials at four public merger meetings | 3.75 mills, unchanged since 1994 |
| Typical mailing address | Mars, PA 16046 | Mars, PA 16046 for most parcels |
| On the Nov. 3, 2026 ballot | Vote to dissolve into Adams Township, forming "Mars Township" | Same ballot question |
The Number That's Actually on the Ballot
Adams Township Supervisors Chairman Russ Ford has told residents at public meetings that the township has not raised its municipal tax rate since 1994. If voters approve the merger this November, Mars Borough's property tax rate would be reduced to match that same 3.75-mill rate once the merger takes effect on January 1, 2028, according to reporting from the 228 Times. At one of the merger's public meetings earlier this year, Ford put it directly to the room, as reported by the 228 Times:
"Every person who lives in the borough of Mars will get a tax decrease."
Mars Borough Council President Mike Fleming has been careful to frame the merger as something other than a bailout. As he told the 228 Times, "It's not a money issue. It's a practicality issue."
Two Outcomes, Neither One Vague
Both sides of the ballot question resolve into concrete, dated outcomes. There's no ambiguous middle scenario.
- If voters in both municipalities approve it on November 3, 2026: Mars Borough's council, mayor, tax collector, and constable positions are eliminated, the combined municipality takes the name Mars Township, and every former borough parcel moves to Adams Township's 3.75-mill rate and code of ordinances starting January 1, 2028.
- If voters reject it: the two municipalities are barred from pursuing another merger vote for five years, according to WPXI's reporting on the referendum terms.
- Either way, addresses stay put. Asked directly whether the merger would change mailing addresses, Ford told the Butler Eagle, "It will not in any form."
For anyone comparing a home in the borough to one on Osona Lane, that means the current tax and governance split is either going away for good in about 17 months, or it's locking in place for at least five years. There's no scenario where the question stays open indefinitely.
What the Blended Zip Code Missed
As of March 2026, listing data put the median home price in Mars, PA at $574,990, with the trailing twelve-month median sale price closer to $557,500, up roughly 7% from the prior year. By June 2026, that same zip code showed a median list price nearer $565,000, down about 5% year over year, with homes spending a median of 39 days on the market. Those are two different reads on direction within the space of a few months, which is itself a sign of a zip code carrying more than one underlying market inside it.
Meanwhile, Coldwell Banker's current market estimate for homes specifically in Adams Township puts the median closer to $599,900. That's not a contradiction of the Mars figures so much as evidence of the blending problem: a number pulled at the zip-code level averages in Mars Borough's smaller, older housing stock alongside Adams Township's newer construction, and the resulting median doesn't cleanly describe either place.
If you're pricing an offer on Osona Lane against a comp that turns out to sit inside the borough, you're not comparing like to like on tax burden, even if the square footage lines up.
Why This Isn't Purely a Tax Story
The merger conversation didn't start with taxes. According to the 228 Times, Ford has said discussions began after officials spent years trying to find a sustainable way to build a new Mars Area Public Library while keeping it in downtown Mars, rather than asking Adams Township taxpayers to fund a building located outside the township. From there, the conversation expanded to the two municipalities' existing shared infrastructure, most notably the Breakneck Creek Regional Authority, the joint sewer authority Ford has valued at $200 million, built through decades of cooperation between the two governments. Mars Borough currently holds a 35% ownership stake in that authority, which would fold into the merged municipality if voters approve.
That shared history is part of why officials describe the merger as consolidation rather than rescue. Neither municipality carries outstanding municipal debt, and both sides have said the combined government would gain expanded police coverage, additional public works staffing, and a clearer path toward finally building that library, benefits that go well beyond a single mill rate.
The Commute Backdrop, on the Same Timeline
Separate from the governance question, the road that runs through this entire corridor is also mid-transformation. PennDOT's Three Degree Road Intersection Project, a $55.8 million safety overhaul of Route 228 through Middlesex and Adams townships, is on track for substantial completion in November 2026, the same month as the referendum, according to PennDOT's own project updates. The work has added turning lanes, a new roundabout, sidewalks, and a jughandle system to reduce the congestion that's long defined this stretch near Mars Area High School.
Butler County is also seeking a $61 million federal grant to fund the final, most expensive segment of the Route 228 corridor, the 3.2-mile stretch between Franklin Road in Cranberry Township and Pittsburgh Street in Adams Township, with work anticipated to begin in early 2027 if the funding comes through, according to the Cranberry Eagle. None of that depends on how the merger vote goes, but anyone weighing a purchase near Osona Lane this fall is effectively watching two separate, unrelated projects resolve within months of each other.
What This Means Before You Write an Offer
If you're looking at a home on Osona Lane or anywhere else carrying a Mars, PA 16046 address, the mailing address alone won't tell you which government's tax rate applies to that specific parcel. Butler County's property records will. Before comparing price per square foot against a listing elsewhere in the same zip code, it's worth confirming which municipality actually assesses the property you're considering, because that answer currently comes with two very different tax histories attached to it.
If your closing lands before January 1, 2028, the currently governing rate applies regardless of how the vote goes, since the merger's effective date is fixed even if approved in November. If you're buying with a longer horizon in mind, the outcome of a single vote this fall determines whether that borough-versus-township tax gap disappears for good or stays exactly where it is for the next several years.
FAQ
Will my mailing address change if the merger passes? No. Township officials have stated the merger would not alter mailing addresses, postal service, or utility accounts in any way.
If I close on a home in Mars Borough before 2028, do I get the new lower tax rate right away? No. Even if voters approve the merger in November 2026, the new municipality and its unified 3.75-mill rate don't take effect until January 1, 2028.
What happens if the referendum fails? State process requires a minimum five-year wait before Mars Borough and Adams Township could bring another merger question back to voters.
Comparing a listing on Osona Lane to one downtown in Mars isn't as simple as running a zip code search, and this November's vote is about to make that distinction matter more, not less. If you want a clear read on which side of that line a specific address actually falls on before you make an offer, Zita Billmann can walk through the parcel record with you and help you request a free home valuation that accounts for it.