Know before you go
- Unincorporated Cobb carries 30.13 mills in 2026; the city totals run from 30.13 in Mableton to 39.63 in Powder Springs.
- Marietta has its own school system, so a Marietta bill carries no Cobb County school levy.
- Cobb’s basic $10,000 homestead exemption saves $271.60 a year on county and school taxes.
Cobb County lies northwest of Atlanta and had an estimated 793,345 residents in July 2025, according to the Census Bureau. It has seven cities, Acworth, Austell, Kennesaw, Marietta, Powder Springs, Smyrna and Mableton, and a large unincorporated area that has no city government at all. Marietta is the most familiar name, but where you live in Cobb is mostly a question of tax district.
The 2026 rates, city by city
The Cobb County Tax Commissioner publishes a one-page sheet each year. For 2026 the county levies are the same across the county, 8.46 mills for county general, 2.97 mills for county fire and 18.70 mills for the county school district, and each city adds its own rate. Totals for a home in each area:
| Tax district | County bill rate | City rate | Total mills |
|---|---|---|---|
| Unincorporated Cobb | 30.13 | – | 30.13 |
| Mableton | 30.13 | 0.00 | 30.13 |
| Marietta | 8.46 | 22.662 | 31.122 |
| Austell | 27.16 | 8.25 | 35.41 |
| Smyrna | 27.16 | 8.99 | 36.15 |
| Acworth | 30.13 | 8.95 | 39.08 |
| Kennesaw | 30.13 | 9.15 | 39.28 |
| Powder Springs | 30.13 | 9.50 | 39.63 |
Georgia applies these rates to 40 percent of a home’s fair market value. On a $400,000 home before exemptions, 30.13 mills is about $4,821 a year and 39.63 mills is about $6,341. The difference comes almost entirely from the city portion.
Why Marietta looks different
Marietta’s county bill rate is only 8.46 mills because Marietta addresses do not pay the county fire levy or the Cobb County school levy. Marietta has its own school system, Marietta City Schools, and its own school tax of 17.97 mills, which the city collects along with 2.867 mills for city general and 1.825 mills for city bonds. The total, 31.122 mills, ends up close to the unincorporated county rate, but the money goes to different places, and the school your child attends follows the city line. More on how independent city systems work is in Atlanta-Area School Districts Explained: County Systems, City Systems and Your Tax Bill.
Tip: In Cobb, the Tax Commissioner bills county, fire, school and special district taxes, and each of the seven cities bills and collects its own city taxes. A city homeowner can receive two bills.
Marietta, Smyrna and Kennesaw in numbers
| Measure (2020-2024) | Marietta | Smyrna | Kennesaw | Cobb County |
|---|---|---|---|---|
| Population, July 2025 estimate | 63,574 | 57,513 | 37,970 | 793,345 |
| Median home value | $448,500 | $449,500 | $335,400 | $407,200 |
| Median gross rent | $1,586 | $1,739 | $1,845 | $1,730 |
| Owner-occupied rate | 47.2% | 59.4% | 64.6% | 67.0% |
| Mean commute (minutes) | 27.5 | 29.8 | 28.6 | 29.4 |
Marietta has the lowest median rent of the group and a lower owner-occupied rate than the county, so a large share of the city is rental housing. Kennesaw has the lowest median home value and the fastest growth: its population estimate rose 14.3 percent between April 2020 and July 2025. Smyrna’s median value is nearly the same as Marietta’s, with a higher share of owners.
Renting in Cobb first
Across Cobb County the median monthly cost for owners with a mortgage was $2,084 in the Census Bureau’s 2020-2024 figures, against a median gross rent of $1,730, a gap of $354. In Marietta the gap is $584, with owner costs of $2,170 and rent of $1,586. Those are narrower gaps than in the City of Atlanta, where the difference is $712. Renting for a year while you learn the county is still a common choice, and the state’s deposit and repair rules apply the same way here; see Renting in Georgia: Security Deposits, Repairs and Your Rights as a Tenant and the full comparison in Rent vs Buy in Metro Atlanta: What the Census Numbers and Georgia Rules Say.
Exemptions in Cobb
The Cobb rate sheet notes that the basic $10,000 homestead exemption, without a floating exemption, saves a homeowner $271.60 a year, not counting savings on city taxes. That figure is $10,000 of assessed value times the 27.16 mills of county general and county school taxes. Cobb is also on the Georgia Department of Revenue’s list of counties with a local exemption that freezes or limits growth in assessed value. To apply, see The Georgia Homestead Exemption for Atlanta-Area Buyers: Who Qualifies and How It Floats.
Getting around
MARTA’s rail lines run through Fulton and DeKalb counties; none of its 38 stations is in Cobb. MARTA’s fare page lists CobbLINC, Cobb County’s transit service, among the regional operators that connect with it. For most Cobb residents daily life involves a car, and the Census Bureau’s mean commute for the county is 29.4 minutes. If you will work downtown or near the airport, test the drive at rush hour before you commit; MARTA and Commuting in Atlanta: Lines, Fares, Parking and Commute Times has more on commuting.
How to choose within Cobb
- Decide whether a city government and its services matter to you, or whether unincorporated county land suits you.
- Check the tax district on the county’s property records for each address.
- If you have children, confirm whether the address is in Marietta City Schools or the Cobb County School District.
- Compare the 2026 total millage for that district with the table above.
- Drive the commute at the time you would make it.
Cobb’s figures sit in the middle of the metro on most measures. For a wider comparison with Fulton, DeKalb and Gwinnett, see Where to Live in Metro Atlanta: Comparing Cities and Counties by Cost, Commute and Taxes and Atlanta-Area Property Taxes by County: 2026 Rates for DeKalb, Cobb, Gwinnett and Fulton.