Background: Supraclavicular brachial plexus block is a vital regional anesthesia technique for upper limb surgeries. Optimization of local anesthetic and adjuvant combinations, such as ropivacaine and dexmedetomidine, significantly impacts the efficacy and safety of this block. Objective: This intervention study aimed to determine the optimal volume of a ropivacaine and dexmedetomidine mixture for ultrasound-guided supraclavicular brachial plexus blocks to enhance analgesic duration while minimizing adverse effects. Methods: A prospective randomized controlled trial enrolled 120 ASA I and II patients scheduled for upper limb surgeries. Patients were divided into four groups receiving varying volumes of the ropivacaine and dexmedetomidine combination. Analgesic duration, onset time, and adverse effects were assessed as primary and secondary outcomes, respectively. Results: Groups receiving higher volumes demonstrated prolonged analgesia, with Group C exhibiting the longest duration. Onset times of sensory and motor blockade did not significantly differ among the groups. Incidences of adverse effects varied, with moderate volumes showing increased instances of nausea and larger volumes associating with higher bradycardia occurrences. Conclusion: Optimizing the volume of ropivacaine and dexmedetomidine in supraclavicular brachial plexus blocks influences analgesic duration without markedly affecting onset times. Balancing efficacy and safety is pivotal in determining the optimal volume for improved perioperative pain management strategies.