Scottsdale and Paradise Valley are both in Arizona's millionaire hub, but it's clear why one suburb is more expensive than the other.

When Phoenix and Scottsdale were expanding in the decades following World War II, the town of Paradise Valley was established to keep the area strictly residential without strip malls or businesses to suck away the rural vibe, according to the town's website. It's just 15.5 square miles, according to the Paradise Valley Chamber of Arizona.

Today, the town has about 14,000 residents and is still mostly residential, save for a few resorts, schools, restaurants, and golf courses.

BI reported in 2023 that Californians have been flocking to Paradise Valley over the last decade. The average resident owns a multimillion-dollar estate and makes $220,000 a year.

With an average listing price of $5.5 million, according to Realtor.com, the town's homes at the bases of Camelback and Mummy mountains are grand estates with pools, outdoor kitchens, and sprawling yards.

Established in 1951, Scottsdale is 185 square miles and currently has 243,000 residents, according to the city.

During my trip, I noticed that Scottsdale was much more developed than Paradise Valley. On the southern end, Downtown Scottsdale is full of high-end shops, dining, and luxury resorts.

Meanwhile, North Scottsdale is home to the city's priciest real estate, with homes as expensive as $54 million, according to Realtor.com.

While mostly residential, I spotted some business, shopping, and dining blocks in North Scottsdale, including the outdoor shopping mall, Scottsdale Quarter.

Up there, the clientele is similar to Paradise Valley — entrepreneurs, C-suite executives, retirees, and medical professionals, Shawn Shackleton, a local luxury real-estate agent who has sold homes in both towns for the last 20 years, told BI.

According to Shackleton, one of the reasons Paradise Valley is more expensive than Scottsdale is its prime location.

According to Shackleton, Paradise Valley sits between Phoenix and Scottsdale, giving residents a country-style refuge 15 to 20 minutes away from downtown Phoenix, the airport, and Biltmore, the area's financial district.

Downtown Scottsdale is similar in distance to Phoenix, but since most of the luxury homes are in the northern area, Scottsdale's wealthiest residents may live a 40-minute drive from Phoenix.

I noticed that most homes were far apart in Paradise Valley. Shackleton told BI that the lot sizes are generally larger in Paradise Valley than in Scottsdale — typically between one and 27 acres.

Shackleton told BI that having a lot of space is ideal for many clients who want to live in a sprawling, one-story home.

"Some people are coming from big cities where they're used to having two-story houses and small yards. And here we have the ability to have single-level homes," she said. "If you go single-level, or ranch, as most people call it, then that means a little bit more land and a higher price point."

In Scottsdale, most neighborhoods had a typical suburban layout with homes sharing side yards.

Unlike Paradise Valley, most homes for sale in Scottsdale have less than an acre of land, according to Zillow, with the largest properties in North Scottsdale.

During my trip, I toured one of the most expensive neighborhoods in the city — Silverleaf Village, located within the 4,000-acre DC Ranch residential community.

I saw some large, sprawling custom homes in Silverleaf, but according to Shackleton's YouTube video, even there, most properties are less than 10 acres.

According to Shackleton, Paradise Valley's large lots and gated driveways give high-profile residents a sense of privacy.

"When you get up into the higher price points, many of the houses in Paradise Valley are individually gated," Shackleton said. "Some like the feeling of being their own private estate."

Many of North Scottsdale's neighborhoods are gated within residential communities and have 24-hour guards, like DC Ranch, Desert Mountain, and WR Estates.

This gives the residents privacy and security from the public, but not necessarily their neighbors.

Since most homes in North Scottsdale are in residential communities, residents who want to build homes choose from a select set of models and floor plans approved by the community.

And due to Scottsdale zoning laws, they can't pick where on the property the home is built, Shackleton said in the YouTube video.

According to the same video, Paradise Valley has fewer residential communities and zoning laws regarding real estate development, resulting in diverse neighborhoods that defy the cookie-cutter stigma of suburbia.

As a non-millionaire, I was skeptical that I'd even be able to tell the difference between these two luxurious suburbs. But after my trip, it's clear why only one is known as the "Beverly Hills of Arizona."