Maine has a cost of living index of 112 relative to the US average of 100. This is above the national average. A FIRE portfolio in Maine needs to stretch further. Many FIRE practitioners in ME plan for a higher withdrawal need or consider relocating to lower-cost states.
The 4% safe withdrawal rule suggests a FIRE number of 25x annual expenses. At Maine's median income of $64,800, that is $1,620,000. However, if you plan to spend more (or less) than median income in retirement, scale the number accordingly.
Maine taxes income at 5.8%–7.15%. In FIRE, your primary income comes from portfolio withdrawals, dividends, and capital gains. Long-term capital gains in ME are taxed at the same rate as ordinary income, including IRA withdrawals. Factor this into your withdrawal rate planning.