If its price tag of nearly $3.5 million isn’t standing in the way of you buying a handsome Tudor mansion in River Forest, there’s another stumbling block:

The house comes with a delinquent property tax bill for almost $96,000 that must be paid before a sale can go through.

The five-bedroom mansion at 1105 Park Ave. is one of 44,873 residential properties in Cook County whose 2014 property tax payments, due in 2015, are unpaid and now delinquent, according to the office of Cook County Treasurer Maria Pappas. That’s roughly 3.7 percent of the residential property in the county.

In all, delinquent homeowners owe the county more than $127.1 million in 2014 tax bills due last year, according to data from Pappas’ office. It’s the highest in the past four years and well above the $71.2 million total for the 2005 tax year, the last year before the housing bust. Cook County collects the taxes for itself and other taxing bodies including school districts, park districts and the city of Chicago.

Of the nearly 45,000 homes with delinquent tax bills, more than half––23,911—are in the city. Tax delinquencies are heavily concentrated in the South Side and south suburbs of the city, in areas where home values have laid low since the housing crash.

In Calumet Township, which contains Blue Island and Calumet Park, about 19 percent of all residential property was hit with a delinquency letter last week. In Thornton Township, the southeast corner of the county, encompassing towns like Dixmoor, Harvey and Markham, it’s 13 percent.

“We’ve seen a lot of joblessness, vacant homes, home values dropping,” said Mary Ryan, the Calumet Park village administrator. “Paying the taxes is hard for people to afford.”

Ryan said she hears regularly from homeowners “who know they can’t walk away from the house because there are consequences to that, but they don’t have the money to cover the taxes.” Many are senior citizens on fixed incomes, she said.

Under Illinois law, property owners who let the tax bill go delinquent into the next year are subject to the county offering it for sale to third parties, who hold the taxes during a redemption period, which is 2½ years for residential tax bills. If the homeowner fails to pay off the bill and redemption fees during that period, the tax owner can eventually move to get title to the house, although it rarely comes to that in the case of owner-occupied homes, county treasurer officials said.

The dream of taking title to that River Forest house for only the cost of its back taxes is just that, a dream. Ultimately, Cook County collects at least 95 percent of the property taxes that are due.

Sometimes, homeowners who fall into delinquency were trying to pay the taxes on their own, instead of through an escrow account managed by the home’s mortgage lender, said Bill Kouruklis, chief deputy treasurer for Cook County. In many cases, “their lender comes in and covers the tax bill,” he said, “because the bank wants to be the first lienholder on the property, not the second after Cook County.”

This year’s Cook County delinquent taxpayers owe as little as $113 and as much as the $95,628 due on the River Forest mansion.

That’s the biggest delinquency of any homeowner in Cook County, and more than $10,000 more than the second-biggest delinquent bill, $85,000 for a home on Fox Lane in Winnetka.

Of the 10 biggest delinquencies, all with past-due bills of $49,000 or more, five are in Chicago. River Forest and Oak Park each have one, and Winnetka has three—two on the same block of Indian Hill Road.

The agent on the River Forest mansion, Kelly Cox O’Brien of Gloor Realty, said the seller is disputing the bill. The home is not in foreclosure.

“We have a certificate of error,” she said. “That tax bill is crazy.”

The Cook County Recorder of Deeds identifies the seller as John M. Cox Jr. O’Brien said he’s related to her, but she declined to comment further.