We present results from Washington CT _ { 1 } photometry for eleven star fields located in the western outskirts of the Small Magellanic Cloud ( SMC ) , which cover angular distances to its centre from 2 up to 13 degrees ( \approx 2.2 - 13.8 kpc ) .
The colour-magnitude diagrams , cleaned from the unavoidable Milky Way ( MW ) and background galaxy signatures , reveal that the most distant dominant main sequence ( MS ) stellar populations from the SMC centre are located at an angular distance of \sim 5.7 deg ( 6.1 kpc ) ; no sign of farther clear SMC MS is visible other than the residuals from the MW/background field contamination .
The derived ages and metallicities for the dominant stellar populations of the western SMC periphery show a constant metallicity level ( [ Fe/H ] = -1.0 dex ) and an approximately constant age value ( \approx 7 - 8 Gyr ) .
Their age-metallicity relationship ( AMR ) do not clearly differ from the most comprehensive AMRs derived for almost the entire SMC main body .
Finally , the range of ages of the dominant stellar populations in the western SMC periphery confirms that the major stellar mass formation activity at the very early galaxy epoch peaked \sim 7-8 Gyr ago .