Medicare Supplement Plans in Castle Rock, Colorado: What to Know for 2027

Original Medicare covers a lot — but it leaves gaps, with no yearly limit on what those gaps can cost you. For many people in Castle Rock, Colorado, a Medigap policy is how they get peace of mind. Here's how the standardized plans work in Douglas County, in plain language, with no rankings and no pressure.

New to Medicare around Castle Rock? Start with one fact that clears up a lot of confusion: what's available to you is decided at the county level, and Castle Rock falls in Douglas County (part of Castle Rock area).

There, 59 Medicare Advantage plans are available for 2027. Roughly 51% of people with Medicare in the county have chosen Medicare Advantage over Original Medicare, among the roughly 52,473 residents who are 65 or older.

Below, we lay out the carriers serving the area, how Original Medicare, Advantage, Medigap and Part D relate, the 2027 numbers everyone shares, the enrollment calendar, and free help — all educational, with no plan rankings.

What Medigap does — and doesn't — cover

Think of Medigap as the layer that sits on top of Original Medicare to absorb the costs it leaves you: the deductibles, the 20% coinsurance, the copays that otherwise have no annual ceiling.

The catch that trips people up is that these plans are federally standardized — a Plan G from one insurer covers exactly what a Plan G from another does. So the letter defines the benefits, and price and service are what separate companies. Medigap doesn't include drug coverage, so most people in Castle Rock, Colorado pair it with a stand-alone Part D plan.

Below we break down what each standardized plan covers and the enrollment rights that matter most in Castle Rock, Colorado. It's a framework, not a ranking — and we don't quote premiums.

Medicare SupplementCastle Rock, CO

The 2027 numbers, from shared to plan-specific

Start with what's fixed for everyone. The standard Part B premium is $202.90 per month in 2026 (2026 amount; 2027 figure will be posted when CMS releases it), and Part A is premium-free for most people who paid Medicare taxes long enough while working.

On the drug side, Part D has real guardrails for 2027: a deductible capped at $700 and, a hard $2,400 ceiling on your out-of-pocket costs for covered prescriptions — the old coverage gap is gone.

Higher earners pay more for Parts B and D through an income-related adjustment called IRMAA, which for 2026 starts above $109,000 in annual income for an individual and is based on your 2024 tax return. Most people fall below that line and pay the standard amounts. The 2027 brackets will be posted when CMS releases them.

Everything past that is plan-specific: the premiums, copays, and coverage details of an individual Advantage or Medigap plan change from plan to plan and year to year. Rather than quote or rank those, we point you to Medicare's Plan Finder and a licensed agent for your exact numbers.

When you can enroll or make changes

Medicare's enrollment windows are federal — the same nationwide — so the timing below applies wherever you live.

Your first window (IEP). When you're new to Medicare, your Initial Enrollment Period is the 7-month window around your 65th birthday month. Signing up on time helps you avoid late penalties that can follow you for years.

Annual Enrollment Period (AEP). Each fall, from October 15 – December 7, anyone with Medicare can join, switch, or drop a Medicare Advantage or Part D plan. Changes take effect January 1.

Medicare Advantage Open Enrollment. From January 1 – March 31, if you're already in an Advantage plan you get one chance to switch plans or return to Original Medicare.

Special Enrollment Periods can also open after certain life events, like moving or losing other coverage. The interactive calendar further down lays the year out visually.

Where to get free, unbiased help near Castle Rock

Good Medicare help exists and it's free — you don't have to figure this out solo or pay for guidance.

For official specifics and the Plan Finder tool, go straight to Medicare.gov or 1-800-MEDICARE (TTY 1-877-486-2048). And a licensed agent can compare options and handle the paperwork with you.

One note on who we are: MyMedicarePlans.org is an independent, privately owned educational resource — not Medicare, not a government agency, and not affiliated with one. Our job is to help you get oriented, then hand you off to the official sources and licensed professionals for plan decisions.

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