We aimed to evaluate the impact of age, sex, and their interactions with provoking risk factors for deep vein thrombosis (DVT). In addition, we intended to provide additional insights on risk factors associated with the isolated distal versus proximal presentation of first symptomatic acute DVT, both being characterized by different prognosis. In the present analysis from the SWIss Venous ThromboEmbolism Registry (SWIVTER), we compared demographic and baseline characteristics in patients with isolated distal (n = 184; 35%) versus proximal (n = 346) DVT of the lower limbs without symptomatic pulmonary embolism, and identified factors related with the presenting thrombosis location. In the overall population, mean age was 59 ± 19 years, 266 (50%) were women, 106 (20%) patients had cancer, 86 (16%) recent surgery, and 52 (10%) acute infection/sepsis. In a multivariable analysis, recent surgery [odds ratio (OR) 2.92, 95% confidence interval (CI) 1.80-4.73] was independently associated with a diagnosis of isolated distal DVT, whereas cancer (OR 2.01, 95% CI 1.20-3.35), male sex aged 41 to 75 years (OR 2.21, 95% CI 1.33-3.67), and acute infection/sepsis (OR 2.71, 95% CI 1.29-5.66) with a diagnosis of proximal DVT. In SWIVTER, age, sex, and several provoking risk factors for VTE appeared to be related with the presenting location of first symptomatic DVT. Cancer, male sex, and acute infection/sepsis were associated with a proximal location of DVT, whereas recent surgery was associated with a distal presentation, likely acting as confounders for the association between thrombosis location and prognosis.