Comparing Chicago’s annual real-estate charts from 2006 to the ones that appeared in the October 2010 issue of the magazine, I found that the average length of time that a house waits on the market has more than doubled in 29 Chicago neighborhoods and 129 suburbs. The two places where market time has lengthened the most over those four years are Montclare on Chicago’s Northwest Side and Lake Forest on the North Shore.

In 2006, Montclare was thriving, thanks to still-affordable bungalows and a smattering of reasonably priced new construction. What’s more, Galewood, a city neighborhood adjacent to Oak Park, was also up-and-coming. (Midwest Real Estate Data, which provides the information for our charts, includes Galewood sales in the Montclare neighborhood.)

But the downturn has been hard. Adjacency isn’t a big draw now that prices have dropped far enough to make the centerpiece places—such as Oak Park, in Montclare’s case—more affordable.

In Lake Forest, the extended market time is the result of two factors, according to a pair of agents there. “We have sellers who were told [a few years ago] that they had a $4 million house,” says Marina Vernon, a Griffith, Grant & Lackie agent. “They hope we’re wrong when we say it’s now $3 million.” But when priced for today’s market, Vernon says, Lake Forest houses sell as swiftly as they ever did; she’s had two high-end homes sell recently in less than 120 days.

Deb Fischer at Koenig & Strey Real Living adds that, at the upper reaches of the market, “it has been slower than other price points in Lake Forest.” While she says the upper bracket has shown some recent signs of life, for a long while that realm was hit by a three-way combo: the difficulty of obtaining jumbo mortgages; buyers having trouble selling their smaller homes in order to move up; and the fact, Fischer says, that “these are usually discretionary purchases.”

Here are the ten suburbs where the average time it takes to sell a house has grown the most. (I’ve excluded towns with fewer than 20 sales for the year.) The column on the far right shows that in Lake Forest, for example, it takes on average 3.58 times as long to sell a house now as it did in 2006.

Here are the ten city neighborhoods where the average time it takes to sell a house has slowed down the most. These figures are for single-family home sales only. (Again, I have excluded neighborhoods with fewer than 20 sales for the year.) The column on the far right shows that, in Montclare, for example, it takes on average 3.97 times as long to sell a house now as it did in 2006.