La-doped intermetallic single crystals of ${{\mathrm{Ce}}_{1}}_{\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{In}}_{3}$ were synthesized via an In self-flux method throughout the entire range $(x=0--1)$. The prototypical heavy-fermion compound ${\mathrm{CeIn}}_{3}$ shows an antiferromagnetic phase transition at 10.1 K and becomes superconducting near a critical pressure where ${T}_{N}$ is completely suppressed. As the La concentration increases, Ce moments are diluted, and the lattice constant increases linearly, satisfying Vegard's law. The electrical resistivity of the high-quality single crystals of ${{\mathrm{Ce}}_{1}}_{\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{In}}_{3}$ shows a gradual suppression of ${T}_{N}$ to 0 K at approximately ${x}_{c}=0.65$. The sign of the slope of the low-temperature resistivity vs temperature changes from positive to negative in the vicinity of the critical concentration ${x}_{c}$, indicating a change in the Kondo ground states from the Kondo lattice to the Kondo impurity state. In the Kondo lattice state $(x<{x}_{c})$, the coherence temperature $(=50\phantom{\rule{0.16em}{0ex}}\mathrm{K})$ assigned as the peak in the resistivity is almost independent of the La concentration. In the Kondo impurity state $(x>{x}_{c})$, on the other hand, a kinklike feature in the resistivity appears at $\ensuremath{\sim}50\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ and persists up to $x=0.97$, indicating a change of the Kondo scattering owing to the crystalline electric field effects. These results suggest that the critical concentration is closely connected to the emergence of the Kondo coherence state.