Cross sections for 180° deuteron electrodisintegration have been measured near threshold for the Q2 range 1.21 to 2.77 (GeV/c)2. The data are compared to several nonrelativistic meson-nucleon and hybrid quark-hadron models. The data are in strong disagreement with the impulse approximation, indicating the importance of non-nucleonic degrees of freedom. None of the models are in good agreement with the data at all values of Q2. The ratio W1/W2 of inelastic structure functions has been extracted using previous forward angle data and is found to decrease strongly near threshold, also indicating the importance of interaction effects.