The 2026 401k contribution limit is $23,500 ($31,000 if you are 50+). In District of Columbia, pre-tax contributions reduce your taxable income at both federal (22%–37%) and DC state (4%–10.75%) levels. Annual tax savings on a full contribution: $7,696.
District of Columbia taxes 401k and traditional IRA distributions as ordinary income at up to 10.8%. On a $90,800/year retirement income, that is $9,761 per year in state tax. Consider Roth 401k contributions if you expect to retire in DC and your future bracket is similar to today.