What Will macOS 10.16 Be Called: Mammoth, Monterey, Skyline, or Something New?

Every year heading into WWDC, one question on many Mac fans' minds is what Apple will choose as the name for the next version of macOS. The tradition dates all the way back to the beginning of Mac OS X with its big cat names, and then in 2013 Apple shifted to Calfornia-themed names with the unveiling of OS X Mavericks.

macos 10 16 names
Back in the early days after the debut of OS X Mavericks, we discovered a total of over 20 California-themed trademark applications filed by various limited liability companies that were all but certain to be shell companies created by Apple to hide its identity.

Over time, some of the trademarks like Yosemite, Sierra, and Mojave were indeed used by Apple for its major Mac operating system updates, while trademark applications for many of the other names have been abandoned.

In last year's lead-up to WWDC 2019, we noted that of that original set of trademark applications, only four unused ones remained active: Mammoth, Monterey, Rincon, and Skyline. All four of those trademarks had been granted by the U.S. Patent and Trademark Office, and Apple was keeping them alive for potential use by filing successive extension requests.

Trademark recipients have up to 36 months from the date of approval to file a Statement of Use proving they are using the trademark in commerce, although they are required to file for extensions every six months during that period to keep that full window open.

Apple of course opted to name its 2019 macOS release Catalina, which wasn't one of the previously trademarked names, but in case Apple has opted to go back to its original list, we decided to check back on last year's trademark list to see if any of them remain protected.

Of the four, Rincon is no longer active, having been abandoned in September 2019 after its 36-month window expired. The other three remain active for now, with Apple's presumed shell companies continuing to file extensions as needed.

  • Mammoth, which is likely related to Mammoth Lakes and Mammoth Mountain, a popular area for skiing and hiking in the Sierra Nevada mountains, saw its trademark application approved in March 2019, and a second extension of the Statement of Use period was approved in March 2020. The full 36-month window won't expire until March 2022 as long as additional extensions continue to be filed.
  • Monterey, a historic city and popular vacation spot on the Pacific coast, has long been one of the most popular macOS name options among our readers over the years. The trademark was applied for by Asilomar Enterprises LLC in December 2013, but wasn't allowed until June 12, 2018. A fourth extension to Statement of Use window was granted just last week, and Asilomar will have until June 2021 to prove commercial use of the name, provided a final extension is requested in December of this year.
  • Skyline likely relates to the scenic Skyline Boulevard that largely follows the ridge of the Santa Cruz Mountains running south from San Francisco, and Antalos Apps LLC filed for a trademark on the name in December 2013. The trademark was allowed on March 20, 2018, and the fourth Statement of Use extension was granted in March of this year. The owner will have until March 2021 to prove use of Skyline in commerce, provided all necessary extensions are requested.

So what will macOS 10.16 be called? Mammoth, Monterey, and Skyline all seem like reasonable options, but we've also seen Apple turn to names that had not been previously rumored. In years when the new macOS version is viewed as more of a refinement of the previous version rather than a leap forward, Apple has used names that bear relationships to the previous ones, such as going from Yosemite to El Capitan and Sierra to High Sierra.

With macOS 10.16 again seeming to be more of a refinement release, could we see something like macOS Channel Islands (the island group that Catalina is a part of) or macOS Avalon (the only city on Catalina)? Or with Apple reportedly set to begin transitioning to its own Arm-based chips for its Mac lineup, could it shift gears to something completely different? Whatever it ends up being, we'll know one week from today.

Related Forum: macOS Big Sur

Popular Stories

iPhone 17 Pro Iridescent Feature 2

iPhone 17 Pro Clear Case Leak Reveals Three Key Changes

Sunday August 31, 2025 1:26 pm PDT by
Apple is expected to unveil the iPhone 17 series on Tuesday, September 9, and last-minute rumors about the devices continue to surface. The latest info comes from a leaker known as Majin Bu, who has shared alleged images of Apple's Clear Case for the iPhone 17 Pro and Pro Max, or at least replicas. Image Credit: @MajinBuOfficial The images show three alleged changes compared to Apple's iP...
iPhone 17 Pro Dark Blue and Orange

iPhone 17 Release Date, Pre-Orders, and What to Expect

Thursday August 28, 2025 4:08 am PDT by
An iPhone 17 announcement is a dead cert for September 2025 – Apple has already sent out invites for an "Awe dropping" event on Tuesday, September 9 at the Apple Park campus in Cupertino, California. The timing follows Apple's trend of introducing new iPhone models annually in the fall. At the event, Apple is expected to unveil its new-generation iPhone 17, an all-new ultra-thin iPhone 17...
iphone 16 pro ghost hand

iPhone 17 Pro: 5 Reasons Not to Upgrade This Year

Monday September 1, 2025 4:35 am PDT by
Apple will launch its new iPhone 17 series this month, and the iPhone 17 Pro models are expected to get a new design for the rear casing and the camera area. But more significant changes to the lineup are not expected until next year, when the iPhone 18 models arrive. If you're thinking of trading in your iPhone for this year's latest, consider the following features rumored to be coming to...
xiaomi apple ad india

Apple and Samsung Push Back Against Xiaomi's Bold India Ads

Friday August 29, 2025 4:54 am PDT by
Apple and Samsung have reportedly issued cease-and-desist notices to Xiaomi in India for an ad campaign that directly compares the rivals' devices to Xiaomi's products. The two companies have threatened the Chinese vendor with legal action, calling the ads "disparaging." Ads have appeared in local print media and on social media that take pot shots at the competitors' premium offerings. One...
iOS 18 on iPhone Arrow Down

Apple Preparing iOS 18.7 for iPhones as iOS 26 Release Date Nears

Sunday August 31, 2025 4:35 pm PDT by
Apple is preparing to release iOS 18.7 for compatible iPhone models, according to evidence of the update in the MacRumors visitor logs. We expect iOS 18.7 to be released in September, alongside iOS 26. The update will likely include fixes for security vulnerabilities, but little else. iOS 18.7 will be one of the final updates ever released for the iPhone XS, iPhone XS Max, and iPhone XR,...
iPhone eSIM Feature

Apple Hints at iPhone 17 Models Lacking SIM Card Slot in More Countries

Sunday August 31, 2025 8:52 am PDT by
Another hint has surfaced that Apple is preparing to eliminate the physical SIM card tray from iPhones in more countries this year. In particular, a source familiar with the matter has informed MacRumors that retail employees at Apple Authorized Resellers in the EU are required to complete a training course related to iPhones with eSIM support by Friday, September 5. There are 27 countries...

Top Rated Comments

jayducharme Avatar
68 months ago
Mac OS Cluster****
Score: 40 Votes (Like | Disagree)
MakeAppleAwesomeAgain Avatar
68 months ago
I don't care as long as they don't release new features and just focus on getting macOS stable again.
Score: 40 Votes (Like | Disagree)
nfl46 Avatar
68 months ago
macOS Snow Catalina

?
Score: 39 Votes (Like | Disagree)
TheSkywalker77 Avatar
68 months ago
macOS High Catalina.

Unoriginal joke, I know.
Score: 33 Votes (Like | Disagree)
Lounge vibes 05 Avatar
68 months ago

MacOS Weed
Yeah, because after a year with Catalina, Weed is what we need
Score: 22 Votes (Like | Disagree)
casperes1996 Avatar
68 months ago
I'm hoping for macOS Redwood
Score: 21 Votes (Like | Disagree)