Abstract This paper examines the effect of proposed tax reform on interjurisdictional household mobility. Specifically, it shows how the elimination of state and local tax deductibility and tax rate reductions would affect total tax liability for two groups of otherwise identical taxpayers, located in twenty different jurisdictions, and then discusses the likely mobility responses. The paper concludes that proposed tax reform would widen tax liability gaps between high and low tax jurisdictions, especially for young and wealthy taxpayers. The resulting “mobility impulse” would be substantial, especially between neighboring jurisdictions. Actual mobility would depend, however, on a host of complicating factors that are discussed. Whether or not the mobility impulse translates into actual mobility, tax reform would create problems for high tax jurisdictions.